求解cd-tn-11 Q7 语法题，希望各位大牛能指导一下~

shirlypp

In Scotland

, the number of wild salmon have been reduced because of uncontrolled deep-sea and coastal netting, by pollution, and by various other threats to the fish’s habitat.

A.number of wild salmon have been reduced because of uncontrolled deep-sea and coastal netting

B.number of wild salmon is reduced because deep-sea and coastal netting is not controlled

C.numbers of wild salmon has been reduced because of uncontrolled deep-sea and coastal netting

D.wild salmon’s numbers are reduced by deep-sea and coastal netting that is not controlled

E.wild salmon’s numbers have been reduced by uncontrolled deep-sea and coastal netting.

正确选项是e，可是不明白为什么number要用复数，时态要用现在完成时~~

12604698

我记得number作"数目＂讲时可以可数吧。lz查辞典确认下吧。后面by一致的只有e了。用现在完成时表明对现在有影响。

dreamistrue

Number的用法小结

1)    a number of / numbers of + 可数名词复数 + 动词复数
2)    the number of + 可数名词复数 + 动词单数
3） the numbers　of  100%错，没有这个结构
4） numbers作为核心词，表示可以被具体化的几个数
530. New Jersey has one of the five highest numbers of reported cases of Lyme disease in the United States.
908. Upset by the recent downturn in production numbers during the first half of the year, the board of directors, at its quarterly meeting, raised the possibility of
adding worker incentives.
因为每个公司的生产指标有很多，所以用复数形式的production numbers。比较题No.492，在那里family dwellings per capita只可以被具体化为一个数。
这些情况下，如果明确知道有多个数字，就用numbers。再例如Don't judge a team by its numbers.不能仅仅从数字（指标）上判断一个队（的好坏）。如NBA队伍中每个球员都有rebound, assist, turnover, score等指标，球队有胜率，排名等指标。这些指标就是由多个数字表达的，所以即使team是单数，但是its + numbers是最合理的。上面的句子也可以改写为：Don’t judge a team by those numbers listed on its website.

5)    numbers作为核心词，但可以被具体化的几个数倾向不明显
OG-verbal-72. The gyrfalcon, an Arctic bird of prey, has survived a close brush with (A) extinction; its numbers are now five-times greater than when the use of DDT was sharply restricted in the early 1970’s.
因为动词是复数，所以可推知numbers是number的复数形式，而不是什么固定用法。
TTGWD9-Q7: In Scotland, the (E) wild salmon’s numbers have been reduced by uncontrolled deep-sea and coastal netting, by pollution, and by various other threats to the fish’s habitat.  
另外，一些讨论中说：numbers是复数做“人数，鸟群”讲。Longman字典：Visitor numbers increase in the summer.　游客人数在夏季增加。现代英汉词典：Birds gather in large numbers beside the river.鸟儿一群群地聚在河边。但是显然后面一个例子中in large numbers是做副词用，参见5)。
这一类用法是最难的，还没有找到最有说服力的解释。但是作题的时候，我们可以借用其他方面的线索，排除错误项。

yanwang1018

并且后面注意以下是and 连接3个By 得并列成份呢

paopao20

1）A' s numbers= the number of A: 讲的都是A的数量，只是因为单复数不同，后面的动词形式也不同了；
2）现在完成时强调一个过程，从过去到现在。这个要根据意思的理解，Gmat还是‘逻辑为王’的。这些因素造成的数量减少是个不断累积的过程。

rainbowmanutd

个人以为完成时是因为原句用的完成时，除非明显错，否则不要改变原句时态

shirlypp

恩，谢谢大家了，很受用。昨天期中考试，现在才看到~~