is就是一类的助动词,直接把它提到句首构成一般疑问句。
Is this his pencil?
肯定回答:Yes, it is.
否定回答:No, it isn't.
Is this his pen? 肯定Yes,he is否定 no he isn't
Is this his pencil?
Yes,it is.
No,it isn't.
Is this his pencil?yes,this is . no,this isn't
Is this his pen? Yes this is. No this is not