I wonder why Mr Green hasn’t showed up at the meeting yet.—I’m not sure，but he________in a traffic jam driving here.

(2013·宁夏银川一中高三第四次考试)It was terrible. The car ________ break down just as we were going on our holiday.

She as well as her classmates________English very much.

We consider ____ absolutelynecessary that we should open our door to the outside world.

Air quality in our city is becoming worse and worse.—Yes. These days’ PM2.5 readings are frightening. Wemust do something to ______air pollution.