____ in wet sand, the vegetables can ______ fresh for a long time.

21All parents are willing to risk ________ their lives tosave ________ of their children when a disaster is approaching

Do you know what he_______ two years ago —Yes，He was fat then.

16. The story that follows _____ two famous characters of the Rocky Mountain gold rush days.

6. After a successful operation, Ronaldo has begun to do some exercise to ____ strength.