--- Credit cards are       useful when travelling.—True. They save us the trouble of taking too much cash.

Wang Ping hesitated for ___ before he ___ to the question.

No matter how much time I spend planning a class, little things still _____ go wrong. So I had no perfect class and I reflected all the time.

—Was Martin sorry for what he had done? —_______. It was just like him.

I  , but my mother didn’t   .