10．I met my headmaster 　　　 　my way 　　　 　school.　

9．You'd better make the best use 　　　 　your time.　

8．The girl is good 　　 　 the computer.　

7．The children often play 　　　 　the playground.　

6．Will you please help me 　　　　　my English?　

5．The boys jumped 　　　　　　the lake.　

4．The girls were swimming 　　　　 　the river at that time.　

3．There is a bridge 　　　　 　the river.　

2．They worked from morning 　　　　 　night.　

across, in, by, on, till, for, over, with, under, into, to, at, of

1．The boat is passing 　　　　　　the bridge.