41. While play is important at all levels of human development， _________ takes on particular significance when children are five and six years old.

A. it

B. and

C. which

D. because it

答案：A

分析：缺主語(yǔ)。it 在這里作為形式主語(yǔ)。

參考譯文：比賽對(duì)各個(gè)層次人的發(fā)展都是重要的，尤其是當(dāng)小孩5、6歲大的時(shí)候，意義重大。

42. During the second and third years of life， children gain _________ over their bodies.

A. control increasing

B. increasing to control

C. control is increasing

D. increasing control

答案：D

分析：缺賓語(yǔ)，而且應(yīng)該是 adj.修飾名詞，只能選D.

參考譯文：在生長(zhǎng)的第二第三年，小孩們對(duì)自己的身體控制能力增強(qiáng)了。

43. All brass instruments use a mouthpiece _________ into a long cone-shaped tube.

A. is inserted

B. that inserted

C. that is inserted

D. and inserted

答案：C

分析：that引導(dǎo)一個(gè)定語(yǔ)從句，mouthpiece為先行詞。A 出現(xiàn)兩個(gè)謂語(yǔ)動(dòng)詞，錯(cuò)；B，D應(yīng)該用被動(dòng)；

參考譯文：所有的銅管樂(lè)器都用一個(gè)放在長(zhǎng)錐筒形管里的吹嘴。

45. By the mid-twentieth century， United States presidential staffs， _________ had numbered fewer than ten a century earlier， numbered in the hundreds.

A. as

B. that they

C. which

D. and

答案：C

分析：非限制性定語(yǔ)從句，只有which能引導(dǎo)非限制性定語(yǔ)從句

參考譯文：到20時(shí)間中期，美國(guó)的總統(tǒng)部官員達(dá)到了幾百個(gè)，而在一個(gè)世紀(jì)前，還屈指可數(shù)呢。

46. In 1966 only 60 percent of all five year olds in the United States attended kindergarten， _________ in 1985 almost 82 percent did so.

A. with

B. which

C. whether

D. while

答案：D

分析：整個(gè)句子中出現(xiàn)了兩個(gè)謂語(yǔ)，缺連接詞。

參考譯文：在1966年，所有5歲的小孩中只有60％的參加了幼兒園，而到1985，幾乎有82％的小孩上幼兒園了。

47. _________ industries， inventions， and communal endeavors of the Shakers， the best known is their fine furniture.

A. Of the many

B. Their many

C. Are the many

D. Many of the

答案：A

分析：倒裝結(jié)構(gòu)。當(dāng)prep短語(yǔ)位于句首，且謂語(yǔ)動(dòng)詞為系動(dòng)詞時(shí)，則引起倒裝。

參考譯文：在基督震蕩教徒所參與很多工業(yè)、發(fā)明創(chuàng)造和社區(qū)建設(shè)中，最聞名的是他們做的優(yōu)質(zhì)家具了。

48. Most fishes and many reptiles have ribs along most of the spine， but in mammals _________ only in the chest area.

A. they are found

B. finding them

C. in which they are found

D. are found

答案：A

分析：缺主語(yǔ)和謂語(yǔ)。該句不是定語(yǔ)從句。

參考譯文：大多數(shù)魚類和很多爬行動(dòng)物沿著大部分脊柱都長(zhǎng)有肋骨，但哺乳動(dòng)物的肋骨只長(zhǎng)在胸部位置。

49. Although the habitat of the American beech tree is now confined to the eastern United States and southeastern Canada， _________ extended as far west as California.

A. where it once

B. once

C. it once

D. and once

答案：C

分析：缺主語(yǔ)。A，D中的where， and 多余。

參考譯文：盡管美國(guó)山毛櫸樹(shù)的生長(zhǎng)地現(xiàn)在只限制在美東和加拿大東南部的狹窄地帶，它曾經(jīng)都延伸向西生長(zhǎng)遠(yuǎn)到加州的地方。

50. Most of North America receives _________ some form of continuous plant cover except in the arid and semiarid Southwest.

A. moisture to sustain sufficient

B. sufficient moisture to sustain

C. to sustain sufficient moisture

D. sufficient to sustain moisture

答案：B

分析：缺賓語(yǔ)。其中形容詞修飾名詞，不定式表“目的”。A，C，D語(yǔ)序混亂。

參考譯文：除了干旱和半干旱的西南地區(qū)，大部分北美地區(qū)通過(guò)吸收充足的潮濕而保持一些連續(xù)植被的形式。