1）the sun rises＿ in the east and falls＿ in the wast.
2)failure is the monther of success＿．
3）li lei joined us in＿ planting trees last week.
4)whose＿ umbrella can this be?
5)he prefers history to＿ math .
6)don't count your chickens before＿ they are hatched.
7)you'd better＿ not go out for a swim on your own.
8)when you don't know a word , you many look it into＿ in your dictionary.
9)if you eat hamburgers every day . you'll get fat＿ .