以下说法正确的是A、HBV不同亚型之间没有交叉免疫，免疫后各亚型之间不能交叉保护B、我国乙肝发病率

The function of the sentence "A nice day, isnt it？" is______.

A．informative

B．phatic

C．directive

D．performative

请帮忙给出正确答案和分析，谢谢！

机体对HBV有免疫力的指标是

A.A

B.B

C.C

D.D

E.E

请帮忙给出正确答案和分析，谢谢！

Which of the following sentences is an emphatic sentence(强调句)？

A．What he means, in other words, his intentions is more annoying than his words.

B．His intentions instead of his words have annoyed me.

C．I was annoyed by his intentions rather than what he means.

D．It is what he means rather than what he says that annoys me.

请帮忙给出正确答案和分析，谢谢！

传染性强的指标（俗称大三阳）是

A.A

B.B

C.C

D.D

E.E

请帮忙给出正确答案和分析，谢谢！

顶棚有直接式和悬吊式两种，其中悬吊式称为吊顶。()