Much of mankind's attitude toward the sea can be traced（追溯）to a misplaced faith in its clearly limitless resources．The shallow muddy water over continental shelves is indeed rich in biological resources；but we are already exploiting almost all the fish，oil and minerals they have to offer．Almost every major fishery has been over-fished already，and there is no reason to expect that others will get along any better．Neither will the fisheries of the future add to our total protein（蛋白质）and one sixth of our animal protein from the sea，and we cannot increase that proportion very much by fishing farther out to sea．We have already seen how simply but completely the depth of the open ocean limits its biological productivity．
We could get more food from the sea if we used its resources more sensibly．A large proportion of the fish we catch we do not eat．We feed it to pigs，or we put it on fields to feed plants which are fed to cattle，and then eaten．Each time we feed fish to something lower down the food chain than ourselves，we lose 90 percent of the nutritional（营养的）value due to the“rules”governing the transfer（转移）of energy．When we eat meat raised on the plants fertilized（使丰饶）with fish meat，we get only one-tenth of one percent of the energy stored in the fish．
1．We can infer from the passage that __________．
A．shallow seas remain untouched in biological resources
B．shallow seas are being used up completely in biological resources
C．shallow seas are still richer in biological resources than deep seas
D．shallow seas are not so rich in biological resources as deep seas
2．According to the passage，it is true that __________．
A．the sea has limitless resources
B．we cannot get more food from the sea
C．the fisheries of the future will GREatly decrease their production
D．the depth of the open ocean limits its biological productivity
3．If we used sea resources more properly，__________．
A．we could live all the better
B．we could fertilize the plants with more fish
C．we could get more pig and cattle meat
D．we could extract more protein from the sea
4．From the last paragraph we know that __________．
A．we haven't used our sea resources sensibly
B．we feed fish to something lower down the food chain than ourselves
C．we don't yet understand at all the“rules”governing the transfer of energy
D．forest fires do harm to mankind
5．The underlined word“proportion”in paragraph 1 means __________．
A．protein B．fishery C．resource D．rate
参考答案：1．B 2．D 3．D 4．A 5．D
