---- ____?    ---- Maybe the possible solutions to the air pollution.

I don’t think you have made great mistakes, _______?

It is the first time that Martin has been to the South Pole, ________?

---John and Tom, you two clean the classroom today, _____? ---But we cleaned it yesterday.

When you are dressed in the latest style, dancing to the most fashionable music after watching the latest film, you feel great,______?

This is the first time that your parents have been abroad, ______?

There must have been a large number of tourists in Sanya during the past Spring Festival, __________?

I don’t think Ken did such a stupid thing，            ？

I don’t think his daughter is able to mend a computer, ________?

-- ________ does it take you to water the flowers?    

Reading books is very important for developing the students’ understanding of the world, ____?

Such a hard problem ________ that I ________ gave it up . 

It was not until the 18th century that man realized that the whole of the brain was involved in the working of the mind，　　　　？

 He hardly reads English out aloud at home, ________?

You had one of your teeth pulled out yesterday, ______? 

I don’t think she will come to the meeting on time,      ?

 -----Li Ping told me that he overslept this morning. -----Oh, he rarely used to oversleep, ________?

She must be in the classroom,           ?

---Jack , you shut the window quickly,______? ----Ok!Oh! The window is broken.

 Listen! His family must be quarrelling, ___________ ?