In time of serious accidents, ________ we know some basic things about first aid, we can save lives.
| A．whether | B．until | C．if | D．unless |
Are you all right?
| A． | That's OK | B． | I think so | C． | Take it easy | D． | It's very kind of you |
The terrible accident almost_____ the driver his life.
| A．valued | B．counted | C．took | D．cost |
Once out of the earth’s gravity, the astronaut is____by the problem of weightlessness.
| A．affected | B．effected | C．related | D．offered |
The beauty of the place ______ them to pause in their hike and rest a while.
| A．allowed | B．switched | C．invited | D．addicted |
The spacewalk performed by Chinese astronaut Zhai Zhigang on Saturday afternoon _____a major breakthrough in China's space program
| A．predicted | B．told | C．marked | D．signed |