We __________ obey the traffic rules.
—Did you have any problems in London ?—Yes, I have trouble ______ Chinese food like noodles.
—What is a writing brush, do you know?—It’s used ______ writing and drawing.
He used to ____in the sun, but now he is used to ____at night.
My father isn’t in good health now. I think he should pay attention____ exercise.
— Don’t worry. He’ll come and help you.—_______he doesn’t come?