some thing表示一些事情,一些东西.
something表示某些事情,强调某些这个不确定性.1.There must be something wrong with you.
2.特殊：It's really something.俚语：很棒的意思.
any thing用于疑问句氏,表示一些事情,一些东西.Is there any thing there?
anything表示任何事情,也是强调不确定性,多用于否定句式.1.I wouldn't like anything that you give me.
2.I don't want anything to eat.