it　可作主語,也可作賓語
it's ＝it is / has 　是作主語,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 hal an hour .
is 是動詞,與 it it's 沒有聯(lián)系呀
加油!不明白再問!是不是一般疑問句用Is 肯定句用It's it 我還是用點(diǎn)不明白可以這樣說吧，如It's a book .Is it a book ?It 呢？前面不是說了嗎？IT　作主語或賓語。The book is interesting . I like it very much .?。ㄗ髻e語）Is it a book ?（作主語）