请看下面这道时态考题：

―When __________ again?

―I don’t know. But when he __________，I’ll let you know.

A. he comes，comes                                  B. will he come，will come

C. he comes，will come                             D. will he come，comes

【分析】此题应选D。第一句为特殊疑问句(when=何时)，根据句意，应用一般将来时态。 第二句为一个含有条件状语从句的主从复合句(when=当……的时候)。按语法规则：在时间状语从句和条件状语从句中，通常要用一般现在时表示将来意义，而不能直接使用将来时态。请做以下选择题：

1. The football match will be put off if it ________.

A. will rain                                                  B. rains

C. rained                                                     D. is raining

2. ―Can I join your club，Dad?

―You can when you _________ a bit older.

A. get                                                          B. will get

C. are getting                                               D. will have got

此时要特别注意分清：由when和if引导的从句是状语从句还是宾语从句：

3. 1) I won’t go if it ________ tomorrow. (状语从句)

2) I don’t know if it ________ tomorrow. (宾语从句)

A. rains                                                   B. will rain

C. is raining                                             D. has rained

答案：1. B 2. A 3. 1)A 2)B