-----where has his brother been ?
------No one knows. He has returned home safely but his missing made the police _____ .
| A．to puzzle | B．puzzling | C．puzzled | D．be puzzled |
——Tom is never late for work. Why is he absent today?
—— Something _____to him.
| A．must have happened | B．can have happened |
| C．must happen | D．can happen |
—— Could you tell me his telephone number?
—— _____the phone book and find it out yourself.
| A．Look up | B．Search for | C．Refer to | D．Go through |
Don’t all stand up together! ________, please.
| A．Each at one time | B．One at a time | C．One by one time | D．One for each time |
______from space, the earth, with water _____seventy percent of its surface looks like a blue ball.
| A．Seen; covered | B．Seen; covering | C．Seeing; covered | D．Seeing; covering |
Roads in this mountain area used to be ______; people found it hard to travel here.
| A．in poor conditions | B．in good condition |
| C．in poor condition | D．in a poor condition |