6.Sharks have lived in the oceans for over 450million years.There are now about 360species of sharks,whose size,behavior,and other characteristics differ widely.
Sharks range in size from the 0.1meter long dwarf-dog shark to the 18-metre long whale shark-the world's biggest fish.The whale shark,like two other large shark species-the basking shark and the megamouth shark-are harmless to people because they feed on plants and small aquatic animals.
Sharks have extremely sensitive sense organs.Some sharks can detect the scent(氣味) of decaying fish or blood even when it is diluted(稀釋) to only one part per million parts of seawater.They can probably hear underwater sounds that originate as far as 3kilometers away and can tell the direction from which underwater sounds are coming.
Sharks are key predators(肉食動物) in the world's oceans,helping control the numbers of many other ocean predators.Without sharks,the oceans would be overcrowded with dead and dying fish.
Every year,we catch and kill over 100million sharks,mostly for food and for their fins.Dried shark fins are used to make shark fin soup,which makes a profit for the sellers.Other sharks are killed for sport and out of fear.Sharks are vulnerable to overfishing because it takes most species 10to 15years to begin reproducing and they produce only a few offspring.
Influenced by movies and popular novels,most people see sharks as people-eating monsters.This is far from the truth.Every year,a few types of sharks injure about 100people worldwide and kill about 25.Most attacks are by great white sharks,which often feed on sea lions and other marine mammals.They sometimes mistake human swimmers for their normal prey,especially if they are wearing black wet suits.
If you are a typical ocean-goer,your chances of being killed by an unprovoked (無緣無故的) attack by a shark are about 1in 100million.You are more likely to be killed by a pig than by a shark.
Sharks help save human lives.In addition to providing people with food,they are helping us learn how to fight cancer,bacteria and viruses.Sharks are very healthy and have aging processes similar to ours.Their highly effective immune system allows wounds to heal quickly without becoming infected,and their blood is being studied in connection with AIDS research.
Sharks are among the few animals in the world that almost never get cancer and eye cataracts.Understanding why can help us improve human health.Chemicals extracted from shark cartilage(軟骨) have killed cancerous tumors in laboratory animals,and these chemicals may someday help prolong our life.
Sharks are needed in the world's ocean ecosystems.Although they don't need us,we need them.We are much more dangerous to sharks than they are to us.For every shark that bites a person,we kill one million sharks.
18.Which statement best expresses the main idea of the article?B
A.There are many different species of sharks,but only a few of them are dangerous to humans.
B.Sharks are important to the ocean ecosystem and they are a valuable resource for humans.
C.Although some sharks are dangerous to humans,they can help save human lives.
D.Sharks always eat small fishes and they are an essential part of the world's oceans.
19.Which question is NOT answered in the article?A
A.How long does a shark live?
B.How many people are killed by sharks each year?
C.Why are sharks important in medical research?
D.What do humans kill sharks for?
20.It can be inferred from the passage thatA.
A.Movies have given people the wrong impression of sharks.
B.Most sharks are dangerous to humans.
C.Sharks will attack anyone who is wearing black.
D.It is very likely that ocean-goers will be killed by a shark.
分析 本文介紹了鯊魚的有關(guān)信息,如鯊魚的飲食,繁衍以及鯊魚所處的現(xiàn)狀.警告人們要注意保護(hù)鯊魚,因為很多鯊魚都處于滅絕的危險之中.
解答 18-20 BAA
18.答案:B 主旨大意題.根據(jù)最后一段第一句Sharks are needed in the world's ocean ecosystems.根據(jù)倒數(shù)第三段第一句 Sharks help save human lives.
19.答案:A細(xì)節(jié)理解題.根據(jù)第六段第三句Every year,a few types of sharks injure about 100 people worldwide and kill about 25.每年幾類鯊魚在世界范圍內(nèi)傷害約100人,殺死約25人.排除B;根據(jù)倒數(shù)第三段第一、二句Sharks help save human lives.In addition to providing people with food,they are helping us learn how to fight cancer,bacteria and viruses.鯊魚能救人的命.他們正在幫助我們學(xué)習(xí)如何對抗癌癥、細(xì)菌和病毒可排除C;根據(jù)第五段第一句Every year,we catch and kill over 100 million sharks,mostly for food and for their fins.主要用于食物和為了它們的鰭.可排除D.故選A.
20.答案:A 細(xì)節(jié)理解題.從第三段的句子:Influenced by movies and popular novels,most people see sharks as people-eating monsters.可知是電影給了人們對鯊魚的錯誤的觀點.選A.
點評 做閱讀時經(jīng)常犯錯的主要原因是,僅憑讀過文章后殘留在腦海中的一絲印象來勾選答案,這樣便很容易掉入出題人故意設(shè)布下的題目陷阱.所謂閱讀理解,對于題目的理解一定要忠實于原文,因此,每一道題都應(yīng)該與原文作全面的對比與核查,再得出答案.也就是說,閱讀理解的每一道題目,在原文都應(yīng)該有明確的出處,我們把這一出處叫做原文相關(guān)句,(1)排除與原文相關(guān)句主題不一致的選項(2)排除與原文相關(guān)句態(tài)度相反的選項 (3)排除用于過于極端或負(fù)面的選項(4)注意結(jié)合文章主旨和主題去排除.