 Let's have a look at a couple of other problems for students. One more aspect students have trouble with is when we start to introduce what we refer to at the beginning of the presentation, which is semi-modal auxiliary verbs. An example of a semi-modal auxiliary verb is need-to. Let's look at the structure of sentences when we use semi-modal auxiliary verbs such as need-to. I need to work every day, for example. Unlike true-modal auxiliary verbs that don't change their form, if we use the pronoun he, in this case, we add an s. To make a negative, such as I don't need to work every day, we use the auxiliary verb do. The same with the question, do you need to work every day? Again, we're using the auxiliary verb do.