Day 5

實(shí)戰(zhàn)演練

When marine organisms called phytoplankton photosynthesize, they absorb carbon dioxide dissolved in seawater, potentially causingAreduction in the concentration of atmospheric carb o n dioxide,Agas that contributes to global warming.However, phytoplankton flourish only in surface waters where iron levels are sufficiently high.Martin therefore hypothesized that adding iron to iron-poor regions of the ocean could help alleviate global warming.While experiments subsequently confirmed that suchAprocedure increases phytoplankton growth, field tests have shown that such growth does not significantly lower atmospheric carbon dioxide.When phytoplankton utilize carbon dioxide for photosynthesis, the carbon becomesAbuilding block for organic matter, but the carbon leaks back into the atmosphere when predators consume the phytoplankton and respire carbon dioxide.

——GRE OG 2nd Edition, Practice Test 1, Section 4, Verbal Reasoning

For the following question, consider each of the choices separately and select all that apply.It can be inferred from the passage that Martin's hypothesis includes which of the following elements?

A.A correct understanding of how phytoplankton photosynthesis utilizes carbon dioxide

B.A correct prediction about how the addition of iron to iron-poor waters would affect phytoplankton growth

C.An incorrect prediction about how phytoplankton growth would affect the concentration of atmospheric carbon dioxide

答案：A、B、C

答案解析

本題是一道不定項(xiàng)選擇題，要求選出關(guān)于Martin的假設(shè)所有正確的選項(xiàng)，那么我們只能將選項(xiàng)帶入文中，逐一核對(duì)。文中Martin的假設(shè)在第三句“Martin therefore hypothesized adding iron to iron-poor regions of the ocean could help alleviate global warming”（向含鐵量不足的海域加入鐵可能有助于緩解全球變暖）。

選項(xiàng)A“是對(duì)浮游植物進(jìn)行光合作用以利用二氧化碳的正確理解”正確，因?yàn)榍懊嬲f(shuō)浮游生物只在含鐵量足夠高的表層水域活躍，那么增加鐵就會(huì)使浮游植物增加，而浮游植物的增加可以吸收會(huì)導(dǎo)致全球變暖的二氧化碳，所以Martin的假設(shè)是正確地理解了浮游植物和二氧化碳的關(guān)系。

選項(xiàng)B“是對(duì)含鐵量不足的海域加入鐵如何影響浮游生物的生長(zhǎng)的正確預(yù)測(cè)”正確，文中提到“隨后的實(shí)驗(yàn)證實(shí)了這一做法（Martin的假設(shè)中的做法）加快了浮游生物的生長(zhǎng)”。

選項(xiàng)C“是對(duì)浮游植物的生長(zhǎng)如何影響大氣中的二氧化碳的濃度的錯(cuò)誤預(yù)測(cè)”正確，文中提到“現(xiàn)場(chǎng)實(shí)驗(yàn)顯示這種生長(zhǎng)沒(méi)有明顯降低大氣中的二氧化碳”，而前面Martin假設(shè)“向缺鐵水域加入鐵（促進(jìn)浮游生物生長(zhǎng)后）會(huì)緩解全球變暖（即會(huì)減少大氣中二氧化碳含量）”，所以Martin對(duì)于二氧化碳會(huì)減少的預(yù)測(cè)是不對(duì)的，因此選項(xiàng)C也是正確的。

英文重現(xiàn)

When marine organisms called phytoplankton photosynthesize, they absorb carbon dioxide dissolved in seawater, potentially causingAreduction in the concentration of atmospheric carbon dioxide,Agas that contributes to global warming.However, phytoplankton flourish only in surface waters where iron levels are sufficiently high.Martin therefore hypothesized that adding iron to iron-poor regions of the ocean could help alleviate global warming.

解析

1.“when”引導(dǎo)的時(shí)間狀語(yǔ)從句，表示主句的動(dòng)作和從句的動(dòng)作同時(shí)進(jìn)行或者一前一后發(fā)生。此處“when”引導(dǎo)的時(shí)間狀語(yǔ)從句主語(yǔ)為“marine organisms”，謂語(yǔ)是“photosynthesize”。“called phytoplankton”和后面的“dissolved in seawater”都是過(guò)去分詞短語(yǔ)作后置定語(yǔ)，分別修飾“marine or ganisms”和“carbon dioxide”。這類(lèi)后置定語(yǔ)的功能相當(dāng)于定語(yǔ)從句，所以，我們?cè)诶斫鈺r(shí)也可以改成“which are called phytoplankton”和“that is dissolved in seawater”。

2.“potentially causingAreduction in the concentration of atmospheric carbon dioxide”是現(xiàn)在分詞短語(yǔ)作狀語(yǔ)，表示主句動(dòng)作發(fā)生后產(chǎn)生的結(jié)果。一般說(shuō)來(lái)，這種結(jié)構(gòu)的邏輯主語(yǔ)就是句子的主語(yǔ)，比如在這里，執(zhí)行“cause”這個(gè)動(dòng)作的就是“marine organisms”。類(lèi)似的例子如：

They opened fire, killing one of our soldiers.

他們開(kāi)槍?zhuān)蛩懒宋覀兊囊粋€(gè)士兵。（開(kāi)槍的后果就是打死了我們的一個(gè)士兵，執(zhí)行“kill”這個(gè)動(dòng)作的是“they”。）

3.“a gas that contributes to global warming”是前面“atmospheric carbon dioxide”的同位語(yǔ)，“a gas”被后面的定語(yǔ)從句“that contributes to global warming”修飾。由兩個(gè)或兩個(gè)以上同一層次的語(yǔ)言單位組成的結(jié)構(gòu)，其中前項(xiàng)與后項(xiàng)所指相同，句法功能也相同，后項(xiàng)是前項(xiàng)的同位語(yǔ)，常用逗號(hào)連接。

4.“water”一般情況下是不可數(shù)名詞，當(dāng)它以復(fù)數(shù)形式出現(xiàn)時(shí)，意思是“（海、湖、河等的）水域”。此處“surface waters”后面的“where”引導(dǎo)的是一個(gè)定語(yǔ)從句，當(dāng)先行詞為表示地點(diǎn)的詞時(shí)，“where”引導(dǎo)的是定語(yǔ)從句；如果先行詞不是表示地點(diǎn)的詞，例如，如果文中的句子是“However, phytoplankton flourish only where iron levels are sufficiently high”，“where”引導(dǎo)的就是一個(gè)地點(diǎn)狀語(yǔ)從句。

5.最后一個(gè)句子，“hypothesized”后面的賓語(yǔ)從句的主語(yǔ)是一個(gè)動(dòng)名詞結(jié)構(gòu)“adding iron to iron-poor regions of the ocean”。動(dòng)名詞作主語(yǔ)通常表示抽象的動(dòng)作，而不定式作主語(yǔ)通常表示具體的動(dòng)作。

詞義辨析

參考翻譯

當(dāng)被稱(chēng)作浮游生物的海洋生物體進(jìn)行光合作用時(shí)，它們吸收溶入海水中的二氧化碳，可能會(huì)造成大氣中二氧化碳濃度的下降，（大氣中的二氧化碳是）一種導(dǎo)致全球變暖的氣體。但是，浮游生物只在含鐵量足夠高的表層水域生長(zhǎng)繁盛。Martin因此假設(shè)，向含鐵量不足的海域加入鐵可能有助于緩解全球變暖。