Teachers _______ be sensitive to the development level of each student so as to help them better. 

—Excuse me, Mr. Brown. ______ you speak Chinese?—Yes, butt only a little.

 –Look! The boy is running fast! –He might ______ to catch a bus.

—Where are Lucy and Lily?—Oh , the two girls must _______ a game in the garden now.

—We are worried about Tom. Why hasn’t he come back?—Don’t worry. He ______ in a traffic jam.