---I hear the government is going to ___ the air quality with the new standard PM2.5,isn’t it?---Yes, ___ the air pollution will get more serious.
They are looking forward to _____________ to the lecture by the famous professor.
Have you determined ___________?
---Can I help you? ---Yes, I bought this radio here yesterday, but it _____________.
He looked very confident and calm during the test, but __________ he was extremely nervous.
It was a cold winter night, and there wasn’t anyone __________the boy could turn for help in the street.