不定代词:凡不是用来指明代替任何特定名词的代词叫做不定代词。不定代词代替名词或形容词.在句中可用作主语,宾语，表语和定语。不定代词包括：
some, any, no, every
-thing: something, anything, nothing, everything
-one: someone, anyone, anything, everyone
-where: somewhere, anywhere, anywhere, everywhere
-body: somebody, anybody, nobody, everybody
例子：
1)Help! Somebody? Anybody?
2)Where did you go? I went nowhere.
3)Nobody is at home.
4)You are really something.
5)I looked for my book everywhere, but I cant find it anywhere.
6)If you want to go somewhere, if you want to be someone, you must wake up.
7)Since everybody is here, lets begin our class.