英语反义疑问句~1.This is the first time this week he’s had to study

英语反义疑问句~
1.This is the first time this week he’s had to study late,____?
A.isn’t he B.hasn’t it C.hasn’t he D.isn’t it
我想问主句是哪一个啊?怎么判断哪个是主句哪个不是啊?
2.The problem wasn't difficult for him ,was it?
( ).He should have been given a more difficult one.
这题为什么应该填NO,IT WASN'T?
不难就应该用YES……嘛~