在什么是定语?句子成分有哪些?真怎区分?答:当先行词是all, something, nothing 等不定代词时,或者先行词的前面有first, last, only, few, much, some, any, no 等词修饰时,或者先行词的前面有最高级修饰时,一般只用that 而不用which 来引导定语从句: I have explained everything that I can to you. I have explained everything I can to you....