It’s kind ________ you to get a cup of tea for me. [ ]

I don’t know when my son __________back, but when he __________back ,I’ll give you a call

Air quality in our city is becoming worse and worse. – Yes. These days’ PM2.5 readings are frightening. We must do something to _______ air pollution.

_______ does your sister go to school?— At 7 o’clock.

What do you think of Miss Li’s teaching?—Oh, no one teaches ________.