a an are is these this it\'s what 怎么用?

a an are is these this it\'s what 怎么用? 用这些a an are is these this it's what回答下面问题 what's this...可以用This is...还是必须用It’s 来回答?还有What are these/th Is this/that a/an?.. Yes,it is./no,it isn't.2Are these/those What is this怎么回答,是It is+a/an What are these?( ) carrots A.it's B.these a 选择 What's this - ( )"A" A.It's B.It's an C.It's a D.This is This is a book,It's an English book.What's this?急. (1)This is a pen.(2)Are these oranges?（3）What's that in Engl 将下列句子进行单复数互换 These are pens Is this an orange What's tha What's this?——___.(①It's a pen.②This is pen.③This is an pen. 补全英语对话A：1 picture is this?B：It's my father's.A：2 are these b