 What's the difference between can, could and able to from espressoenglish.net? In the present, can and able to are the same. If your boss asks you to take a new project, you could say, Yes, I can take on this project. Or, Yes, I'm able to take on this project. The negative forms are can't and not able to. For example, No, I can't take on this project. No, I'm not able to take on this project. The past forms are could and couldn't and was or were able to. Or wasn't or weren't able to. For example, I wasn't able to finish all my homework yesterday. I couldn't finish all my homework yesterday. Don't say, didn't can. That doesn't exist and it's a common error in English. In the negative form, we can use either one. But in the positive form, we typically use was able to. For example, I was able to leave work early yesterday. In the future, there is only one option, will or won't be able to. For example, I'll be able to work on this project tomorrow. Sorry, I won't be able to go to the party on Thursday. Don't say, will can. This doesn't exist and it's another common error. When you're asking someone to do something, use can or could. Could is a little bit more formal. For example, can you bring me a glass of water? Could you bring me a glass of water? When asking about someone's abilities, you can use either can or able to. For example, can you run a mile in under 10 minutes? Are you able to run a mile in under 10 minutes? Thanks for watching English Tips from Espresso English. If you liked this video, please share it.