用适当的词形填空：
1． If it ___ (rain) tomorrow, I ____ (not go) out.
2． They ___ (come ) to see me if they ____ (have ) time.
3． If he ____ (not know ) the way, he ___ (ask) the others.
4． I ___ (do) a lot of good things if I ___ (have) a lot of money.
5． It’s an exciting week. ( 改感叹句)
6．They have a very good time. ( 改感叹句)
用if, when, before, after, until等连词填空：
1．___ you understand the rule, you will have no difficulty with it.
2. You will stay healthy ___ you do more exercises, such as running and walking.
3. We should try to save the water ___ it is too late.
4.I’ll have to turn off the computer _____ my father comes home.
5.The book was so interesting that he read it for three hours ____ he knew it.
6. I won’t believe that ___ I see it with my own eyes.
7. I won’t go back ___ I reach the Great Wall.