 Welcome to Learning English, a daily 30-minute program from the Voice of America. I'm Ashley Thompson. And I'm Dan Novak. This program is designed for English learners, so we speak a little slower, and we use words and phrases, especially written for people learning English. On today's program, I have a story about scientists that are studying the material of ancient structures to see why they have lasted for so long. Jill Robbins reports on a black ballet school in London. Katie Weaver brings us this week's health report on the approval of a second malaria vaccine. Later, Jill returns with Andrew Smith to present the lesson of the day. But first, ancient builders across the world created structures that are still standing today, thousands of years later. Roman engineers built thick concrete sea barriers, for example. Mayan builders created sculptures to their gods. And Chinese builders raised walls against invaders. But there are many recent structures that are already starting to fail. The concrete that makes up much of our modern world lasts around 50 to 100 years. A growing number of scientists have been studying materials from long ago. They are breaking apart pieces of buildings and reading historical texts, hoping to learn how they have stood for thousands of years. The research has turned up a surprising list of materials that were mixed into old buildings. They include tree bark, volcanic ash, rice, beer, and even urine. These unexpected materials could have the ability to get stronger over time and heal cracks when they form. Figuring out how to copy these features could have real impacts today. While our modern concrete has the strength to hold up very tall buildings and heavy infrastructure, it cannot compete with the endurance of these ancient materials. With the rising threats of climate change, there is a growing call to make construction more sustainable. A recent UN report estimates that the built environment is responsible for more than a third of carbon dioxide emissions worldwide. Cement production alone makes up more than 7% of those emissions. Many researchers have turned to the Romans. Starting around 200 BCE, the Roman Empire was building concrete structures that have stood the test of time. That includes the pantheon to the aqueducts that still carry water today. Even in places where seawater has been hitting structures for ages, you will find concrete basically the way it was when it was poured 2000 years ago, said John Olson. He is an archaeologist at the University of Victoria in Canada. Most modern concrete starts with Portland cement, a powder made by heating limestone and clay to super high temperatures and grinding them up. That cement is mixed with water to create a paste. Then material like rock and gravel are added. Records from ancient builders show the Roman process was similar. The ancient builders mixed materials like burnt limestone and volcanic sand with water and gravel, creating chemical reactions to tie everything together. Now scientists think they have found an important reason why some Roman concrete has held up structures for thousands of years. The ancient material has an unusual power to repair itself. Exactly how is not yet clear, but scientists are starting to find reasons why. Vladimir Masic is a civil and environmental engineer at the Massachusetts Institute of Technology. In a study, he said this power comes from chunks of limestone throughout the Roman material that is not mixed in evenly. Researchers used to think these chunks were a sign that the Romans were not mixing up their materials well enough. Instead, the scientists found that the chunks could fuel the material's self-healing abilities. When cracks form, water enters the concrete, Masic explained. That water activates the leftover lime, creating new chemical reactions that can fill in the damaged sections. Today's builders cannot just copy the ancient processes. Even though Roman concrete lasted a long time, it could not hold up heavy buildings. You couldn't build a modern skyscraper with Roman concrete, Oleson said. It would collapse when you got to the third story. Instead, researchers are trying to take some of the ancient material and add them into modern mixes. Masic is part of a company that is trying to build new projects using self-healing concrete. People do not need to make things last quite as long as the Romans did to have an impact, Masic said. If we add 50 or 100 years to concrete's lifespan, he said, we will require less demolition, less maintenance, and less material in the long run. It was a criticism about her afro-braided hair that led Ruth Essel to create what she calls a safe space for black dancers. The founder of Pointe Black Ballet School in London said when she was a child, teachers and others all but punished her for not following the traditional ballerina way. I'll never forget my first time about to dance on a West End stage, said Essel. That was the time the 10-year-old wore her hair braided at dance practice. Her mother had spent her last $120 to get her hair done. Her happiness disappeared when her teacher pointed at her in an almost all-white group of dancers. The teacher told her to take out her braids because it looked like a mess. That was just one of several times Essel was made to feel bad about being different. These are all things that happened before I was 16 years old. And I didn't know any better, she said. These difficulties led Essel to establish Pointe Black in 2020 at the age of 26. I wanted there to be a black environment. I wanted there to be people who looked like me. I wanted there to be a teacher that looked like me, she said. She said it felt like she was given power when she could finally wear black clothes and shoes rather than the traditional pink color for ballerinas because it was closer to my color. Ballet has expanded across the world with famous ballet dancers from Asia, South America, and Cuba. But many still think of ballet dancers as light-skinned. And classical ballet companies try to have a similar look for dancers in classical works like Swan Lake. That makes it harder for dancers of color. Some 2.2% of dancers at the top four ballet companies in Britain are of black ancestry. That percentage is in line with the country's black population at 3%. A spokesperson noted that keeping diversity is important to everyone at the Royal Academy of Dance, saying dance is for everybody. But Essel wants to speed up change by introducing new ideas. She said her shows use African dances and music. And dancers wear different hairstyles, including twists, rolls, and afros. She added, it's really just about celebrating the person no matter where they come from. Maya Bealspring is a 10-year-old student at Pointe Black and another ballet school. She enjoys exploring different kinds or types of ballet. I get to experience different types of ballet, different music, she said, after a perfect practice for an upcoming show. Essel teaches all the classes in her school. She said, everything about my school is what my younger self would have wanted. I'm Jill Robbins. The World Health Organization, or WHO, approved a second malaria vaccine last week. The decision could offer a less costly and readily available shot to help fight the disease. WHO Director-General Tedros Adonam-Gabrielsis said the UN Health Agency approved the new malaria vaccine based on advice from two expert groups. They suggested the shot could be given to children at risk of the disease. As a malaria researcher, I used to dream of the day we would have a safe and effective vaccine against malaria. Now we have two, Tedros said. Britain's Oxford University developed the new three-shot vaccine along with the Serum Institute of India. Research suggests it is more than 75% effective. The vaccine can protect people for another year with an additional shot called a booster. Tedros said the shot would cost about $2 to $4 and could be available in some countries next year. Earlier this year, health officials in the African countries of Ghana and Burkina Faso also approved the vaccine. Infected mosquitoes spread the parasitic disease when they bite people. This is one more tool we will now have, but it's not going to replace bed nets and spraying insecticides, said John Johnson of the aid group Doctors Without Borders. This is not the vaccine that's going to stop malaria, he added. Johnson was not part of the expert groups that advised the WHO. The WHO approved the first malaria vaccine in 2021. The UN agency described the vaccine development as an historic effort to end the deadly disease in Africa. The continent is home to most of the world's estimated 200 million malaria cases and 400,000 malaria deaths. But that vaccine, known as Moskerex and made by GSK, is only about 30% effective. The treatment requires four shots and becomes less effective within months. WHO experts, however, said the data to date on the GSK and Oxford developed vaccines does not show which one is more effective. The Bill and Melinda Gates Foundation had been one of the GSK vaccines' biggest financial supporters. But the non-profit ended its support for Moskerex last year. It said the GSK shot was less effective than officials would like and that money would be better used elsewhere. The big difference with these two vaccines is access, Johnson told the Associated Press. He noted that about 10 countries or more could get the GSK vaccine in the next few years. GSK has said it can only produce about 15 million treatments a year. The Serum Institute has said it could make up to 200 million treatments of the Oxford vaccine a year. Alistair Craig is with Britain's Liverpool School of Tropical Medicine. He said countries still waiting for the GSK vaccine should turn to the Oxford vaccine instead. If the new vaccine is widely available across Africa, it could greatly reduce severe sickness and deaths caused by malaria in a few years, Craig said. Neither of the vaccines stops transmission of malaria. As a result, immunization campaigns alone would not be enough to prevent epidemics. And reports of resistance to malaria drugs are on the rise. You would be foolish to think that this vaccine is going to be the end of the malaria story, Craig said. In a separate decision, the WHO's expert group also approved the dengue vaccine made by Takeda. European Union drug officials approved the dengue vaccine earlier. The WHO advised that the dengue vaccine be used in children age 6 to 16 in countries where the disease is widespread. Dengue killed almost 1,000 people this year in Bangladesh. I'm Katie Weaver. My name is Andrew Smith. And I'm Jill Robbins. You're listening to The Lesson of the Day on the Learning English Podcast. Welcome to the part of the show where we help you do more with our series, Let's Learn English. The series shows Ana Mateo in her work and life in Washington, D.C. In Washington, D.C., you can get to many places by using the bus or metro train. And a lot of people use bicycles or scooters to get from one place to another. But it can still be useful to have a car. And that's why Ana wants to get her driver's license. The license gives her legal permission to drive a car. To get the license, she has to take her driving test on a Saturday. In Lesson 21 of the Let's Learn English series, Ana's friend Marcia invites her to a party. The party is on Saturday, so Ana thinks she can't go to it because of her driving test. Let's listen. Hey Ana, my friend is having a party on Saturday. Can you come with me? Sorry, I can't come with you. I have to get my driver's license. Will you be busy all day? I don't know. First, I have to take a test on the computer. Then I have to take a test in the car. But you have to take the test during the day, don't you? Yes. Luckily, Ana learns that the party is at night. The party is at night. Oh, then I can come with you to the party on Saturday night. Great. I have to help my friend with the party. Can you help me? Sure, that sounds like fun. In a previous lesson of the day, Andrew and I explained how speakers of English change the pronunciation of the verb can when they talk more quickly. Can changes to can. Listen again to Ana and Marcia. In these sentences, they mostly pronounce the verb can with slower speech. The party is at night. Oh, then I can come with you to the party on Saturday night. Great. I have to help my friend with the party. Can you help me? Sure, that sounds like fun. Everyone has to bring something or do something. You can bring food or you can perform. Really? I can perform? You can. Can you? Yes. I can recite poetry. Did you notice that the more Ana wanted to emphasize or make her meaning clear, the slower she said the word can. Oh, then I can come with you to the party on Saturday night. Speaking a little faster, the pronunciation starts to change. Really? I can perform? And a little later, Marcia says, Ana, maybe you can just bring food. And if Jill quickly tells me that she can help me tomorrow, it sounds like this. I can do it tomorrow. Now we're going to show another example of how we change vowel sounds and reduce words. Reducing means we make words shorter and faster. This next example uses the two words have to. When Ana and Marcia say those two words quickly, the sound changes. First, listen to the slower speech. Sorry, I can't come with you. I have to get my driver's license. Will you be busy all day? I don't know. First, I have to take a test on the computer. Then I have to take a test in the car. But you have to take the test during the day, don't you? Now, listen to the faster speech. First you'll hear Marcia, then Ana. Now I have to go shopping for food. I have to help Marcia shop. Now listen to Jill and me say have to in a short conversation. So Jill, what are you doing later this afternoon? I have to look at the comments on our YouTube channel. How about you? Well, I have to do a lot of things. I have to check my camera. I have to review some notes for a story. I have to go to the grocery store. I have to... What else do I have to do? Oh, I have to clean up some things. And I have to get ready for tomorrow. Whoa, do you really have to do all that? Can't you wait and do some of it tomorrow? I guess I don't have to get it all done, but I'd rather do it sooner. I'd rather means that you prefer to do something or be something. So Jill, would you rather be a hammer or a nail? Well, I don't think I would want to be either. But if I had to choose, I would be a hammer. But I'd rather be a bird than a hammer. Me too. We're going to talk more about the phrase, I'd rather, in another lesson of the day. I'm Jill Robbins and you're listening to the Lesson of the Day on the Learning English Podcast. Now let's go back to Lesson 21. Listen to these two sentences and see if you can identify or name the subject and verb of each sentence. Everyone has to bring something or do something. Nobody recites poetry at parties. Did you hear the subject and verb? In the first example, they were the words, everyone has. And in the second one, they were the words, nobody recites. Recites means to say something aloud, usually from memory, like a poem, speech, or the words to a song. There is something interesting about the subjects of those sentences. In fact, the words are so special that everyone studies them in English class. Andrew, when you think of everyone, do you think of one or more than one person? Well, of course, I think of more than one. Yeah, you're thinking of lots of people. But here is why the word everyone is special. Listen to the example again. Everyone has to bring something or do something. Marcia says, everyone has. Everyone means more than one person. But the verb has agrees with a singular subject. So that's how the word is special. The word nobody follows the same rule. We can think about more than one person when we say nobody. But the verb agrees with a singular subject. Listen. Nobody recites poetry at parties. Here are some more words that can refer to more than one person or thing, but that take a verb that agrees with a singular subject. The words are every, everyone, nobody, somebody, someone, everybody, anybody, and anyone. In English-speaking countries, everybody learns the grammar rule for those words in school. But not everyone remembers them. And some people may not feel it sounds natural to follow that rule with the word every. Here is a sentence you can use to help you remember the rule. Every window needs washing. And here's some words from a song. Everybody loves somebody sometime. Ah, yes, I know that song. Are you going to sing that, Jill? Yeah, everybody loves somebody sometime. Sounds good to me. Thanks, but there's a famous recording of that song by Dean Martin that sounds a lot better. Well, Jill, what's the plan for our next lesson of the day? I'm still working on that, but you just said something that gives me an idea. In lesson 22 of Let's Learn English, Anna is planning her new show for children. Her producer, Amelia, asks her about it. Let's listen. So Anna, what's the plan for the show? When we say, what's the plan for, that's just another way of saying what will happen or what are we going to do? And we say, what's the plan for when we are doing something together with another person or persons? Tune in for our next podcast when we listen in on Anna making plans with her producer, Amelia. Thanks for listening to the lesson of the day on the Learning English podcast. I'm Jill Robbins. And I'm Andrew Smith. And that's our program for today. Join us again tomorrow to keep learning English through stories from around the world. I'm Ashley Thompson. And I'm Dan Novak.