意思:这是什么?
语法:What's this 是特殊疑问句。疑问代词 what 问的是系表结构句子中的表语,回答要用陈述句 This is ......。
特殊疑问句举例
1、 What's your homework?
It's an essay. (it 指代 homework)
2、 When do you have to hand it in?
Tomorrow. (简略回答 = I have to hand it in tomorrow.)