She had to drop out of school _____ her family couldn’t afford the cost of her education.
A. although B. unless C. because D. so
The old man has retired from the factory. He _____ there for 30 years.
A. works B. worked C. has worked D. was working
—I don’t mind telling you what I know.
—You _____. I can manage it myself.
A. mustn’t B. ought not to C. can’t D. don't have to
The decorations were so lovely that they _____ in a short time.
A. sold out B. has been sold out C. were sold out D. were selling out
The students _____ are hard-working and ready to help others should be praised.
A. who B. whom C. which D. whose
—What’s the noise outside?
—Some children_____ hide-and-seek in the yard.
A. were playing B. are playing C. have played D. played
