Although the first part is easy the rest ____.
| A．is supposed difficult | B．are difficult |
| C．has proved difficult | D．could have been difficult |
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 |