21. There is no complete inventory of positions or people in federal service at this level. The lack may be explained by separate agency statutes and personnel systems, diffusion among so many special services, and the absence of any central point (short of President himself) with jurisdiction over all upper-level personnel of the government.
譯文：這個(gè)級別的聯(lián)邦政府官員和職位沒有完整的記載。對此（缺少詳細(xì)記載）所做的解釋可能是，各部門的條例和人事制度各不相同，分布的特殊服務(wù)部門太多并缺少一個(gè)中心機(jī)構(gòu)（總統(tǒng)本人除外）來管理所有的政府高級官員。
22. That sex ratio will be favored which maximizes the number of descendants an individual will have and hence the number of gene copies transmitted.
譯文：那種性別比例能在最大程度上增加一個(gè)個(gè)體所能擁有的后代數(shù)量，并因此能在最大程度上增加所傳遞到后代身上去的基因復(fù)制品的數(shù)量。
23. With the conclusion of a burst activity , the lactic acid level is high in the body fluids , leaving the large animal vulnerable to attack until the acid is reconverted , via oxidative metabolism , by the liver into glucose , which is then sent (in part )back to the muscles for glycogen synthesis.
解釋：本句中修飾成分極多，以分詞修飾和介詞結(jié)構(gòu)修飾為主，作各種類型的狀語。前面的狀語和主句還好理解，從leaving開始句子變難；leaving引導(dǎo)的直到句末的結(jié)構(gòu)來做整個(gè)句子的狀語；分詞中又包含了三個(gè)狀語，其中的兩個(gè)via oxidative metabolism by the liver又起到了插入語的作用，把be converted into拆成兩段。
本句的另外一個(gè)特征是其中充斥著專有名詞。其中的body fluids, oxidative和synthesis通過字面的意思或者根據(jù)詞頭、詞根我們還是應(yīng)該猜出其意思的，lactic acid, metabolism和muscle這三個(gè)詞在生物類文章中極其常用，大家應(yīng)該背下來；而glycogen這種東西則沒辦法，只能作一個(gè)首字母提煉。但是請記住，GRE和GMAT文章中只要出現(xiàn)了這種專有名詞，出題者是一定會(huì)在文章中把它在文章中所乃至的詞義解釋清楚的，所以讀者遇到文章中做了解釋的專有名詞，應(yīng)該力求把解釋看懂。
譯文：隨著爆發(fā)出來的運(yùn)動(dòng)的結(jié)束，再體液中乳酸含量會(huì)變得很高，使得大型動(dòng)物處于容易受到攻擊的狀態(tài)，直到乳酸通過有氧新陳代謝，被肝臟轉(zhuǎn)化成（convert into）葡萄糖，而葡萄糖接下來又會(huì)（部分）傳送回肌肉中重新合成糖原 。
24. Although Gutman admits that forced separation by sale was frequent, he shows that the slaves’ preference, revealed most clearly on plantations where sale was infrequent, was very much for stable monogamy.
譯文：雖然古特曼承認(rèn)，由于奴隸買賣而造成的被迫離散甚為頻繁，但他還是證明，奴隸的偏愛——在那些奴隸買賣并不頻繁的種植園上被最為顯著地揭示出來——在很大程度上側(cè)重于穩(wěn)定的一夫一妻制（monogamy）。
25. This preference for exogamy, Gutman suggests， may have derived from West African rules governing marriage, which, though they differed from one tribal group to another, all involved some kind of prohibition against unions with close kin.
譯文：古特曼表示，這種對于外部通婚的偏愛很有可能緣起于西部非洲制約著婚姻的規(guī)定，盡管這些規(guī)定在一個(gè)和另一個(gè)部落群體之間不盡相同，但都涉及到某種對近親聯(lián)姻（union with close kin）的禁止。
26.Gutman argues convincingly that the stability of the Black family encouraged the transmission of-and so was crucial in sustaining-the Black heritage of folklore, music, and religious expression from one generation to another, a heritage that slaves were continually fashioning out of their African and American experiences.
譯文：古特曼人令人信服地論辨道，黑人家庭的穩(wěn)定有助于包括民間傳說、音樂、及宗教表達(dá)在內(nèi)的黑人文化遺產(chǎn)一代一代傳遞下去，因而在維持文化遺產(chǎn)方面也起著至關(guān)重要的作用，而對于這種文化遺產(chǎn)，黑奴們不斷地從其非洲和美洲的經(jīng)歷中予以豐富發(fā)展。
27. Although some experiments show that, as an object becomes familiar, its internal representation becomes more holistic and the recognition process correspondingly more parallel, the weight of evidence seems to support the serial hypothesis, at least for objects that are not notably simple and familiar.
雖然某些實(shí)驗(yàn)表明，隨著一個(gè)物體變得熟悉起來，其內(nèi)心再現(xiàn)圖像亦更具整體感，辨認(rèn)過程相應(yīng)地更趨于平行，但證據(jù)的砝碼似乎在支持序列假設(shè)（serial hypothesis），至少是對于那些不甚簡單、不甚熟悉的物體來說。
28. Thus, for instance, it may come as a shock to mathematicians to learn that the Schrodinger equation for the hydrogen atom is not a literally correct description of this atom, but only an approximation to a somewhat more correct equation taking account of spin, magnetic dipole, and relativistic effects; and that this corrected equation is itself only an imperfect approximation to an infinite set of quantum field-theoretical equations.
因此，舉例來說，對數(shù)學(xué)家而言，了解到下述情形可能會(huì)令其驚愕不已，即薛定諤（Schrodinger）的氫原子方程式并非是對該原子作出的一種絕然正確的描述，而僅僅是個(gè)近似值，趨近于一個(gè)在某種程度上更為正確的將自旋、磁性偶極子、以及相對論效應(yīng)考慮在內(nèi)的方程式；而這個(gè)得以糾正的方程式就其本身而言也只是一個(gè)不完美的近似值，趨近于無窮無盡的一整套量子場論方程式。
29. In addition, the style of some Black novels, like Jean Toomer's Cane, verges on expressionism or surrealism ; does this technique provide a counterpoint to the prevalent theme that portrays the fate against which Black heroes are pitted , a theme usually conveyed by more naturalistic modes of expression ?
不僅如此，有些黑人小說（比如JT的甘蔗）的風(fēng)格接近與表現(xiàn)主義和超現(xiàn)實(shí)主義；這種技巧是否為流行的主題提供了一個(gè)和諧的對應(yīng)呢？這種主題刻畫了黑人注意與之相抗?fàn)幍拿\(yùn)，這是一個(gè)通常用更為自然主義的表現(xiàn)手法所表達(dá)的主題。
30. Although these molecules allow radiation at visible wavelengths， where most of the energy of sunlight is concentrated, to pass through, they absorb some of the longer-wavelength， infrared emissions radiated from the Earth’s surface, radiation that would otherwise be transmitted back into space.
雖然這些分子允許可見波長（visible wavelength）的輻射——陽光的絕大部分能量就匯集于此——不受阻擋地穿透，但它們卻會(huì)吸收某些較長波長（longer-wavelength），亦即從地球表面輻射出的紅外發(fā)射（infrared emission），這種輻射若不是二氧化碳的緣故就會(huì)被重新輸送回太空。
譯路通武漢漢口翻譯公司整理
2012.7.17