为什么要说“I don't think so”而不说“I'm not think so”

i don't think so 和i'm afraid not I don't think so.I'm afraid not.I hope so.I'm afraid so.四句话的 i don't think so I think,too.I so think.I think so,too.I don't think,too. no,iif I don't think so? I don't think so 翻译中文 i don't think so.怎么翻译? I don't think so是什么意思 I don't think so的中文 I Don't think so 与 I think not 用法的区别 A、No,it isn’t B、I’m afraid not C、I don’t think so D、Yes,it i Don't you think Nick is a good student?I don't think so.为什么不