I’ve had a bad cough recently.—-Me too. I’ve never experienced ______ of air pollution in cities before.

－Shall we goand have a picnic at the weekend—________ It is said there might be snow then.

s a very interesting book． I’ll buy it, _____．

There are still many old city walls in Xi’an,_______—Yes, there are.

You forgot your keys when you left home in the morning.–Good heavens,___________.