There is thick haze(雾霾)around many cities in China recently. What do you think of it —I think __________ cars we drive, the less pollution the city has.

Where is Kate —She is ______.

As more and more restaurants join “clear your plate” campaign, people are encouraged _______ food any more.

known to all language learners, newly learnt words will soon be forgotten unless ______ used in everyday communication.

I am sorry to have kept you for a long time.