6.—He hardly spent any time on his subjects,---------?

1当陈述部分有never,seldom,hardly,few,little,barely,scarcely,nothing 等否定词时,后面的疑问句则表示为：
There are few apples in the basket,are there?
He can hardly swim,can he?
They seldom come late,do they?
2反义疑问句的回答用yes,no,但是,当陈述部分是否定形式时,回答要按事实.如：
They don’t work hard,do they?他们不太努力工作,是吗?
Yes,they do.不,他们工作努力./No,they don’t.对,他们工作不努力
3因此选d