Day 6

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 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.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

It can be inferred that the author of the passage mentions predators primarily in order to

A.help explain why Martin's hypothesis is incorrect.

B.identify one effect of adding iron to iron-poor waters.

C.indicate how some carbon dioxide is converted to solid organic matter.

D.help account for differences in the density of phytoplankton between different regions of the ocean.

E.point outAfactor that was not anticipated by the scientists who conducted the field tests mentioned in the passage.

答案：A

答案解析

題目考查為什么會(huì)提到“predators”，其實(shí)也就是在問(wèn)為什么會(huì)提到“predators通過(guò)呼吸將二氧化碳釋放回大氣中”。淺層的目的自然是進(jìn)一步說(shuō)明上一句提到的“浮游生物的增長(zhǎng)沒(méi)有明顯降低大氣中的二氧化碳”，根據(jù)這點(diǎn)很容易選擇選項(xiàng)B“識(shí)別向缺鐵的水里加入鐵后的一種效果”或選項(xiàng)E“指出進(jìn)行現(xiàn)場(chǎng)試驗(yàn)的科學(xué)家沒(méi)有預(yù)料到的一個(gè)因素”。但這并不是最終的目的，仔細(xì)讀文章可以知道，證明“浮游生物的增長(zhǎng)沒(méi)有明顯降低大氣中的二氧化碳”的目的其實(shí)是反駁Martin的假設(shè)，因?yàn)槌霈F(xiàn)的這種結(jié)果是和前面Martin假設(shè)的向缺鐵的水里加入鐵有助于緩解全球變暖的預(yù)期不一樣的，所以最終證明了Martin的假設(shè)是不對(duì)的，因此選項(xiàng)A“幫助解釋為什么Martin的假設(shè)是錯(cuò)的”是正確答案。選項(xiàng)C“說(shuō)明一些二氧化碳如何被轉(zhuǎn)化成固體有機(jī)物”及選項(xiàng)D“說(shuō)明海洋不同區(qū)域浮游生物密度的差別”在文中并未涉及。

英文重現(xiàn)

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.

解析

1.本句中的“experiment”和“field test”意思都是試驗(yàn)，但是前者主要指在實(shí)驗(yàn)室中做的試驗(yàn)，后者指在現(xiàn)場(chǎng)做的試驗(yàn)。

2.前面我們講過(guò)“while”作并列連詞表示轉(zhuǎn)折，前后內(nèi)容形成對(duì)比的用法，但在這里，“While experiment…phytoplankton growth”中的“while”的卻是另一個(gè)用法，即引導(dǎo)讓步狀語(yǔ)從句，意思為“雖然……，但是……”，多用于句首。

3.第二個(gè)句子的兩個(gè)“when”都是用來(lái)引導(dǎo)時(shí)間狀語(yǔ)從句，表示“當(dāng)……時(shí)”，另外“when”也可以引導(dǎo)定語(yǔ)從句，其先行詞一般是一些表示時(shí)間的詞，在從句中充當(dāng)時(shí)間狀語(yǔ)，如：“I still remember the day when I first met you.”（我仍然記得初次與你見(jiàn)面的那天）。

4.“l(fā)eak into”意思為“泄露、滲入”。例如：

Water had started to leak into the basement.

水已經(jīng)開(kāi)始滲入地下室了。

詞義辨析

參考翻譯

雖然試驗(yàn)隨后證實(shí)了這一做法加速了浮游生物的生長(zhǎng)，但是現(xiàn)場(chǎng)試驗(yàn)卻顯示這種生長(zhǎng)并沒(méi)有明顯降低大氣中的二氧化碳。當(dāng)浮游生物利用二氧化碳進(jìn)行光合作用時(shí)，碳會(huì)變成有機(jī)物的基本組成部分，但是當(dāng)掠食者食用浮游生物并呼吸出二氧化碳時(shí)，碳會(huì)再次泄露回大氣中去。