It is important for an (educate) to understand what makes each student tick. (general) speaking, I usually look their body language. I know when students are really interested, because they lean forward and look at me. People have a (tend) to lean towards whatever they are interested in. so if a student has his head lowered to look at his watch, it implies he is (bore) and just continuing the minutes for the class to end.
A good teacher should also have the strategy (distinguish when students are troubled, and try to inquire is going on about them. Anyway, (react) to body language is an important component for a teacher, duty is helping all teenagers learn (active) and devotedly.
