复合不定代词指的是由some, any, every, no后接thing, one, body等构成的一类代词，它们包括 something, somebody, someone, anything, anybody, anyone, nothing, nobody, no one, everything, everybody, everyone 等。它们在句中通常只用作主语、宾语或表语，不能直接用于名词前作定语。这类代词在用法上应注意以下几点：
1. 若受到形容词的修饰，注意将修饰它们形容词放在复合不定代词的后面，而不是放在它们的前面。如：
There’s nothing wrong with the machine. 机器没有毛病。
句中的wrong是修饰nothing的定语，但只能说成nothing wrong，不能说成wrong nothing。
2. anyone, everyone 等只能指人，不能指物，且其后一般不接of 短语。若是指物或后接 of 短语，可用 any one, every one (即分开写)。如：
any one of the boys (books) 孩子们(书)当中的任何一个(本)
every one of the students (schools) 每一个学生(一所学校)
3. 要注意根据具体语境区分不同复合不定代词的意思，如要分清是指人还是指物，是肯定语境还是否定语境，要做题时不仅要注意选出“正确”答案，而且要选出“最佳”答案。
【考例1】When I returned to my hometown, I was nearly lost. Almost ________ had changed.
A. nothing B. anything C. something D. everything
【分析】答案选D。根据前文的I was nearly lost（我差不多迷路了）可知，家乡变化很大，故空格处填everything比较合适。
【考例2】―How can I make friend的复数形式" target="_blank">friends in a new school?
―Say hello to ________ to you today, and you can have a friend tomorrow.
A. new someone B. someone new C. new anyone D. no one new
【分析】答案选B。由于修饰复合不定代词的形容词总是要置于所修饰的代词之后，所以可排除B和C。根据句意，可知A比D更符合语境。
【考例3】―What did you buy for your daughter at the supermarket?
―I bought ________, because I couldn’t find ________ she likes.
A. something; anything B. anything; something
C. nothing; anything D. something; nothing
【分析】答案选C。根据句中的couldn’t find…she likes可知，说话者“没有找到女儿喜欢的……”，据此语境可确定：第一空填nothing，第二空填anything。