—I can’t find my mobile phone anywhere. —You _____ have lost it while eating out.

—Hurry up , or you ________ catch the train. 

We can do a lot to stay healthy. __________, we should eat a balanced(平衡的) diet.

I can play basketball，but my sister ________．

 –Look! A man is cutting a tree on the moon. --It ______ be true. The teacher said there is no air on the moon.