1. After people have learned that magnets attract things, centuries passed _____ they took note of the fact that magnets sometimes also repel things.
A. before B. until C. after D. since
2. He is off to Paris again tomorrow. He tells me that, with this journey, he _____ there and back twenty times.
A. will be B. will have been
C. will go D. will have gone
3. Many ways have been found _____ small and simple machine to process large and complicated machine parts.
A. by using B. to use C. using D. used
4. I walked down the corridor, my footsteps _______ frighteningly through the empty deserted building.
A. echoing B. echoed C. to echo D. having echoed
5. Apart from personal preferences, social context also affects—both directly and indirectly---the media and the media content to which you become exposed. For example, other members of the family often select media content that you _____ , and you become ex posed to it.
A. would not have selected B. should not have selected
C. must not select D. cannot have selected
1. A before 應(yīng)該理解成“（幾百年過去了，人們）才……”；如果用 after 應(yīng)該是…after cent uries passed they took note of the fact…；如果用 until，應(yīng)該是 they didn't take noteof the fact that…until centuries passed。
2. B 此句意為：“他明天去巴黎，加上這次，他就去了二十次了�！备鶕�(jù)句意，應(yīng)用將來完 成時態(tài)。句中有 back 一詞，故 D 不合適。
3. B to use…，不定式短語做 way 的定語，只是因?yàn)槎ㄕZ太長，故將謂語前移，使句子避免頭重腳輕。by using 表示方式， 做狀語用；using 為動名詞，不能做 way 的定語，way 要求不定式做定語；used，無論從語法結(jié)構(gòu)上還是從意義上都講不通。
4. A 分詞短語做伴隨狀語，my footsteps 與 echo 的關(guān)系是主動的，因此用現(xiàn)在分詞。另外，分詞做伴隨狀語表示與謂語動詞的動作同時發(fā)生，所以用其一般式。
5. A 本句意為：“除了個人喜好外，社會環(huán)境也會直接或間接地影響你使用的媒體和媒體的內(nèi)容。例如，家庭的其他成員常常選擇的媒體內(nèi)容你就未必選，可是你也得使用。”句中暗含了“如果是你，你就不會選”的意思，所以用虛擬語氣合適。should not have selected 表示“本不應(yīng)該選”；must not select 表示“一定不要選”；cannot have selected 表示“一定不能選”，過于絕對。只有 would not have selected 符合句意。
