[求助]请教GWD31之9的Q7~~~~

Q7:

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.

1. number of wild salmon have been reduced because of uncontrolled deep-sea and coastal netting
2. number of wild salmon is reduced because deep-sea and coastal netting is not controlled
3. numbers of wild salmon has been reduced because of uncontrolled deep-sea and coastal netting
4. wild salmon’s numbers are reduced by deep-sea and coastal netting that is not controlled
5. wild salmon’s numbers have been reduced by uncontrolled deep-sea and coastal netting

答案给的是选E.

可是我觉得这里应该用number而不是numbers啊,这里是表示"...的数量".不是吗

是答案错了还是有其他什么原因呢

number可以是复数，我也解释不清

gemj有篇讨论单复数的帖子，LZ可以看看，反正我当时看得是云里雾里的

http://forum.chasedream.com/dispbbs.asp?boardid=23&replyid=169346&id=23189&page=1&skin=0&Star=1