OG16 Q66

brycechen09

[size=15.000000pt]Covering 71 percent of Earth’s surface, the oceans play an essential role in [size=15.000000pt]maintaining the conditions for human existence on land, moderating temperatureby the absorption of heat and carbon dioxide, and giving pure water back to theatmosphere through evaporation.
[size=15.000000pt]A) Covering 71 percent of Earth’s surface, the oceans play an essential rolein maintaining the conditions for human existence on land, moderating
[size=15.000000pt]B) Covering 71 percent of Earth’s surface and playing an essential role inmaintaining the conditions for human existence on land, the oceansmoderate
[size=15.000000pt]C) The oceans cover 71 percent of Earth’s surface and play an essential rolein maintaining conditions for human existence on land, and by moderating
[size=15.000000pt]D) The oceans cover 71 percent of Earth’s surface, play an essential role inmaintaining the conditions for human existence on land, and moderate
[size=15.000000pt]E) The oceans cover 71 percent of Earth’s surface, playing an essential rolein maintaining the conditions for human existence on land, and theymoderate
Parallelism; Rhetorical Construction; Grammatical Construction
This sentence about the essential role oceans play in maintaining conditions forhuman existence on land begins with a participial phrase describing the vastness ofthe oceans, followed by the main clause (oceans play an essential role . . .). Theobject, role is modified by a prepositional phrase that indicates what kind of rolethe oceans play (it plays a role in maintaining the conditions for human existenceon land). This statement about the ocean’s role in maintaining terrestrialconditions is elucidated by two parallel participial phrases that describe the oceans,explaining how they maintain conditions essential for human existence on land(moderating . . . and giving . . .).
A Correct. This version of the sentence effectively conveys the means bywhich the ocean plays an essential role in maintaining the conditions forhuman existence on land, using parallel verb forms.
B This version of the sentence is ungrammatical; and giving . . . suggeststhat this is part of a series of participial phrases, but it is not.
C The conjunction followed by a prepositional phrase and by moderating . . .anticipates a new subject—an agent that does something by moderating—but this subject never appears.
D This version of the sentence is structured as a series of verbs—cover, play,and moderate—all describing things the oceans do; the final participialphrase giving . . . water . . . violates the parallel structure set up in thesentence.
E This version of the sentence correctly makes playing an essential role . . .a function of the oceans’ coverage of Earth’s surface, but the introduction ofa new main verb moderate fails to indicate that what follows (moderatingtemperature and returning pure water) identifies the role oceans play inmaintaining conditions for human existence on land. Furthermore, theparticipial phrase and giving pure water . . . violates the parallel structureset up by the series of main verbs that appear earlier in this version of thesentence.
The correct answer is A.




正答是A，题目我会做，但我没看懂C选项的解释，and by moderating 为什么暗示着一个新的主语呢？？？


THX
                                
                        
               

lfzlxm

C中的and有问题。
and的用法有两种，一是提示平行结构，二是连接两个相对独立的事情。在本句中，根据句义判断moderating是对the oceans play an essential role的补充说明，并不是两个相对独立的事情，同时and+by moderating不和任何成分平行，在这里从句义判断也不应该平行，所以错。另，我感觉og的很多解释都比较神棍，参不透= =。。。