状语从句有很多，其中时间状语从句、条件状语从句是最主要的。它的时态由主从句相呼应来决定，条件状语从句表达将来的情况，但主句为一般将来时，从句为一般现在时态；时间状语从句则“主将从现，主过从过”，过包括一般过去时和过去进行时两种情况。结果状语从句也很重要，其次是原因、目的、让步、方式和比较状语从句，这些从句的时态主从句一致即可。
热身训练
1.The children were leaving school on Tuesday _______ they saw an accident。
A.when B.while
C.because D.after
2.We won‘t go to the park __ it is fine tomorrow。
A.if B.when
C.because D.unless
3.We’ll see Uncle Wang this Sunday if it ___。
A.won‘t rain B.isn’t rain
C.doesn‘t rain
D.didn’t rain
4.——What was the party like？
——Wonderful.It‘s years ___ I enjoyed myself so much。
A. after B.when
C. before D. since
5.None of them knew it ______ the teacher told them。
A. when B. until
C. after D. though
6.——I hope you’ll enjoy your holiday， Tom。
——Thank you， grandma. I‘ll call you ______ I arrive there。
A.as soon as B.when
C.before D.until
7.She ______ Chinese since she came to China。
A.studied B.was studying
C.has studied
D.is studying
8.Someone knocked at the door ______ I was answering the telephone。
A.while B.because
C.but D.as soon as
9.You should make a plan ____ you do everything important。
A.when B.before
C.after D.if
10.——I don’t know _____ he will come tomorrow。
——Don‘t worry. _______ he comes， I’ll let you know。
A.when；If
B.if；Whether
C.if；If
D.whether，Whether
