---What’s your best friend like? --- .
–Look! A man is cutting a tree on the moon. --It ______ be true. The teacher said there is no air on the moon.
All of us went to the park ______ Bob. He had to look after his sister.
I wonder when they ________ for Beijing. I will go to the train station to see them off when they _______.
–Which would you like, tea or coffee? --_______. I really don’t mind.
When the students were playing games on the playground, Jim suddenly stopped _____and began to cry, so we stopped _______ what was wrong with him.