What makes the space shuttle _____ is that it takes off like a rocket but lands like an airplane.
| A．exceptional | B．strange | C．unique | D．rare |
In much of the animal world，night is the time________for sleep－pure and simple.
| A．set aside | B．set down |
| C．set off | D．set up |
Team leaders must ensure that all members ________their natural desire to avoid the embarrassment associated with making mistakes.
| A．get over | B．look over |
| C．take over | D．come over |
Briggs will ________as general manager when Mitchell retires.
| A．get away | B．take over |
| C．set off | D．run out |
Oldfashioned phones matter when wireless networks ________in disasters.
| A．turn down | B．turn out |
| C．break down | D．break out |
Bears ________ fat stores throughout the summer and fall to have energy enough to last them through their winter sleep.
| A．pack up | B．build up |
| C．bring up | D．take up |