The speaker _____ several other subjects in the course of his talk but mostly kept himself to the main topic.
32. It’s important to listen to your teacher carefully in class, so try not to let your mind _________.
31. -Do you mind if I turn off the TV? -__________.
30. Jennifer, who is my best friend, said she would go abroad for further education __________.
29. A good teacher should leave some time for the students to _________ the knowledge.
28. There is no doubt that a small child has to learn to keep its _________ before it can walk far.