问题

For some time the expert __________ people of the health risks caused by passive smoking. He says he won’t stop until all the smokers around him decide to quit smoking.

A:is warned
B:is warning
C:has been warning
D:has been warned;

正确答案是：

同类题型

Using Dr Yuang’s hybrid rice, nowadaysfarmers are producing harvests ________ before.

Could you lend me 50 pence? ______, I’ll have to change a ￡10 note into coins [ ]

This is the bag ________ my mother boughtyesterday

—It’s my ID card.

Nobody knows _______broke into the house last nightand stole the important papers.