复合句使用时的注意事项

⑴宾语从句：在介词之后、动词不定式之前或在or之前，只用whether。如：I can’t decide whether to buy this bike or not.
⑵状语从句：在时间状语从句和条件状语从句中，用一般现在时表示将来时。如：I will tell him about it when he comes tomorrow. He will learn about wild animals if he joins the Wild Animals Club.
⑶定语从句：
①先行词是all, few, little, nothing, everything, nothing等不定代词时，只能用that。如：All that he said is true.
②先行词被only, no, any, all等词修饰时，只能用that。如：This is the only thing that father bought for me.
③先行词是序数词或被序数词修饰时，只能用that。如：This is the second book that I have read.
④先行词是形容词的最高级或被形容词最高级修饰时，只能用that。如：This is the best book that I have read this year.
⑤先行词既包括人又包括物时，只能用that。如：We talked about the people and things that we remembered.
⑥在介词后只能用which。如：The house in which I lived has been sold.