Question

【題目】Peter had been puzzled over the problem for over an hour___________ all at once the solution flashed across his mind.

A.whenB.whileC.thenD.as

Answer 1

【答案】A

【解析】

考查狀語從句連詞。句意：Peter已經(jīng)被這個問題困擾一個多小時了，突然解決方法從他腦海里閃過。A. when當(dāng)……時候；B. while當(dāng)……時候，盡管，然而；C. then然后；D. as當(dāng)，因為，盡管。分析句子可知，此處考查固定句型had done…when…“已經(jīng)/剛做完某事……（突然）就……”，故選A項。