an 和 a 有什么区别怎么运用 It's...It's a...有什么区别怎么运用 有Is this...这个句子吗?

This is 和 It's 有什么区别? 1 lot`s of a lot many some 怎么运用?有什么区别? with pleasure和It's a pleasure有什么区别 It's a Saturday night和It's Saturday night有什么区别? Yes,it is a watch 与yes,it's a watch有什么区别 请问what's this 用 It's V .作答 与用It's a V 作答有什么区别. what's this 回答是It's V 与 这与It's a V 有什么区别? its和it's有什么区别 Its 和It's有什么区别? 这些英语单词有什么区别?怎么运用? It's a cup 和 This is a cup有什么不同 it's not you,is it?和it's you,isn't it?的意思一样么?有什么区别?