Many people
feel that human beings are responsible for the disappearance of some other
animal species. While we may have hastened the disappearance of some, abundant
evidence suggests mankind has had little impact. Biologists point out that 50
species can be expected to disappear in the twentieth century but also remind us
that about 50 species can be expected in the nineteenth century, and 50 species
in each of the centuries before that. Dr. T.H. Jukes at the University of
California has pointed out that about 100 million animal species have become
extinct since life began on Earth about 3 billion years ago. Thus, animals come
and animals go as a natural consequence of something Mr. Darwin discovered. The
human race is a recent newcomer to the scene, so we've had nothing whatsoever to
do with the disappearance of millions of species. In fact, when
it comes right down to it, we're a miserable failure at genocide (种族灭绝). In
spite of an all-out centuries-old war on rats, we haven't made a dent in their
numbers, much less extinguished a single species. And in spite of all our high
technology we haven't been successful in eliminating a single undesirable insect
species! A friend of mine owns most of the Douglas DC-7
aircrafts left in the world. They make excellent spray planes because they can
carry a lot of insecticide and fly for a very long time over great distances.
Last year, his company sprayed most of the western Sahara and the Sahel regions
of Africa to hold down the locusts and grasshoppers. This year, the
environmentalists put pressure on the U.N. to stop it because dieldrin and
malathion might cause an increase in the cancer risk of people in the western
Sahara and the Sahel. As a result, the hoppers and locusts are back by the
zillions and the crops are failing. But the people of West Africa certainly
aren't going to worry about dying of cancer; they are dying of starvation
instead. I've come to the conclusion that the people who are
trying to save the world are probably quite sincere about it but they don't know
much about science and certainly nothing about systems engineering.
单选题
According to the author, which of the following evidence proves that
human beings aren't responsible for the disappearance of some other animal
species?
A. Human beings have hastened the disappearance of some.
B. There was mass extinction long before humanity's time on Earth.
C. Human beings' activities have had great impact on the earth.
D. Many species have extinct since the human race came into being.
【正确答案】
B
【答案解析】[解析] 第一段从第二句到该段结束，论述了一些专家的观点“100 million animal species have become extinct since life began on Earth about 3 billion years ago”，“...we've had nothing what so ever to do with...”中可以知道，作者认为物种的灭绝从很久以前就大量地出现，并非人类出现才给其带来如此大的损失。与B选项一致。
单选题
Which of the following is closest in meaning to the phrase "made a dent
in their numbers" (Sentence 2, para. 2)?