—Peter looked tired and a little absent-minded in class． —He _____ too late．

It is essential that these application forms ______ back as early as possible.

How I wish I _________ him the secret! I regret having done that now. 

The boy suggested that Tom ______ the problem another way, and Tom’s expression suggested that he_________. 

I know it’s normal for such a thing to happen, but we _____ it if we’d been more careful.