We mustn’t be nervous when we are in danger. We should cool.

What do you think of haze(雾霾)？ —- It ____ us we all must try to do something to stop the air pollution.

We have worked out a plan. But I’m not sure whether it will do in .

_________ we go at 7.30 ? －What about __________ it a little earlier ?

He argued _______ smoking, and insisted that it was ________ argument that smoking was harmful to health.