Clearly, in a system _________ every decision is made on the basis of tradition alone, it may be difficult to achieve progress.
A. that B. when C. where D. which
Suddenly it _________ to me that I should report the accident to the police.
A. happened B. struck C. occurred D. hit
The following chapters provide step-by-step instructions for practical _______ of genetic (基因)engineering to agriculture.
A. applications B. organization C. expression D. attention
What a moving _____to see so many people offer help to these in danger!
A. sight B. scene C. view D. scenery
—Please let me know where David is. I couldn’t find him anywhere.
—Well, he _____have gone far—his coat’s still here.
A. shouldn’t B. mustn’t C. can’t D. wouldn’t
He should have come here earlier, but he hasn’t _____yet.
A. turned in B. turned up C. turned on D. turned out
