阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。
As educator, I can know what is going on in my students' minds by observing their body language and then make (adjust) to maximize my class efficiency.
When students lean forward and look at me, I know they are really interested in the lesson. But if a student lowers his head to look at his watch, it implies he is bored. When two students lean (they) heads together, it shows they (write) notes to each other. When a student looks up but there is an absence of eye contact, I guess that he is paying no attention in class.
When a student is (distract), he always looks anywhere but at me. Those are angry，afraid or experiencing anxiety may have their arms (cross) in front of their chests and their legs closed or crossed, like they are guarding their bodies. Students who are sad or worried always wear a frown. If a student doesn't brush her hair and her eyes are red weeping, there must be deeper issues at work.
Ultimately, my duty is helping every student to learn. Their body language lets me know when (change) class activities, when to intervene and when to talk to students (individual). Reacting to body language is an important part of being a teacher.