Man's never-ceasing ______ for knowledge continues to broaden our understanding of the earth's atmosphere.
A. request
B. quest
C. investigation
D. research
The 1986 Challenger space-shuttle ______ was caused by unusually low temperatures immediately before the launch.
A. expedition
B. controversy
C. dismay
D. disaster
我拿到序文,心中______,简直不相信自己的眼睛,我怎么敢接受先生如此高的______想到先生一向对后生晚辈关爱扶持有加,我把这篇序言当成先生对我的鞭策、鼓励和督导,给我提出的一个奋斗目标。 填入划横线部分最恰当的一项是( )。
A. 受宠若惊 期许
B. 诚惶诚恐 褒奖
C. 忐忑不安 评价
D. 惴惴不安 赞赏
He ordered the work ______.
A. started at once
B. to be started at once
C. to start at once
D. at once start