In communication, a smile is usually _____ strong sign of a friendly and _____ open attitude.
| A．the; / | B．a; an | C．a; / | D．the; an |
Rather than ______ on a crowded bus, he always prefers _______a bicycle．
| A．ride; ride | B．riding; ride | C．ride; to ride | D．to ride; riding |
_____ of the students who took part in the military training is 450.
| A．A number | B．A lot | C．Lots | D．The number |
The roads are crowded______ walking to work is even quicker than driving.
| A．in order that | B．so that | C．so as to | D．in order to |
Rather than ______ at home, he prefers ______ out to play football even on a cold day.
| A．to stay; to go | B．staying; to go | C．stay; to go | D．staying; going |
______ you call me to say you’re not coming, I’ll keep waiting for you at the theatre.
| A．Unless | B．When | C．If | D．As |