's缩写It's 是 It is 的缩写's 大部分就是is的缩写类推... 'm缩写I'm是 I am的缩写'm 大部分就是am的缩写类推... 't缩写isn't是 is not的缩写wasn't是 was not的缩写don't是 do not的缩写deson't是 deso not的缩写't 大部分就是not的缩写 'd缩写I'd...
it 可作主语,也可作宾语it's ＝it is / has 是作主语,如It is a book .= It's a book .The book is interesting .I like it very much .It has been open for half an hour .= It's been open for h...