4. Perhaps the most significant postwar trend was the decentralization of cities throughout the United States， _________ when massive highway-building programs permitted greater suburban growth.
    A. and accelerated a phenomenon
    B. a phenomenon that accelerated
    C. accelerating a phenomenon which，
    D. the acceleration of which phenomenon
    答案：B
    分析：考的是同位語結(jié)構(gòu)，a phenomenon是 the decentralization of cities throughout the United States 的同位語。A中and為conj.，后面應(yīng)該連接一個(gè)完整的句子，但缺主語，錯(cuò);C中語序混亂，錯(cuò); D中of which作為介詞賓語，后面應(yīng)該接一個(gè)完整句，但只有一個(gè)phenomenon主語，句子不完整，錯(cuò)。
    參考譯文：可能戰(zhàn)后最重大的趨勢就是美國城市的分散化，當(dāng)大規(guī)模高速公路建設(shè)項(xiàng)目容許了更大程度的發(fā)展郊區(qū)，這個(gè)現(xiàn)象更被促進(jìn)了。
    補(bǔ)充： accelerate/ accomplish/ achieve/ evolve都可以是vi.不接賓語
    5. Ronald Reagan had served two terms as governor of California before _________ President.
    A. he became
    B. when becoming
    C. became
    D. did he become
    答案：A
    分析：before為狀語從句引導(dǎo)詞conj，后面一般引導(dǎo)一個(gè)完整的句子。B同時(shí)出現(xiàn)兩個(gè)狀語從句引導(dǎo)詞，錯(cuò);C缺主語;D應(yīng)該為正常語序，選項(xiàng)中使用了倒裝句式，錯(cuò)。
    參考譯文：里根在成為美國總統(tǒng)之前連續(xù)兩屆擔(dān)任加州的州長。
    6. _________， domesticated grapes grow in clusters， range in color from pale green to black， and contain sugar in varying quantities.
    A. Their botanical classification as berries
    B. Although their botanical classification as berries
    C. Because berries being their botanical classification
    D. Classified botanically as berries
    答案：D
    分析：句子的主語是grapes ， 后面是平行結(jié)構(gòu)grow…， range…， and contain…?？崭窈蟮木渥右淹暾?，那么空格處就應(yīng)該是同位語，狀語從句，分詞等修飾成分。A中Their指代不明，而且classification和berries也不相符，錯(cuò);B中Although為conj.，后面應(yīng)該是完整句，錯(cuò);C中Because為conj.，后面應(yīng)該是完整句，錯(cuò)。
    參考譯文：培植的葡萄的植物分類跟漿果是一樣的，它們成串的長在樹上，顏色從灰白色到黑色，并且包含由不同數(shù)量的糖份。