Some scientists say that animals in the ocean are increasingly threatened（威胁）by noise pollution caused by human beings． The noise that influences sea animals comes from a number of human activities． It is caused mainly by industrial underwater explosions（爆炸）， ocean drilling， and ship engines． Such noises are added to natural sounds． These sounds include the breaking of ice fields， underwater earthquakes， and sounds made by animals themselves．

    Decibels（分贝） measured（测量） in water are different from those measured on land． A noise of one hundred and twenty decibels on land causes pain to human ears． In water， a decibel level of one hundred and ninety﹣ five would have the same effect（效果）．

    Some scientists have planned to set a noise limit（限度）of one hundred and twenty decibels in oceans． They have found that noises at that level can frighten and confuse whales（鲸鱼）．

    A team of American and Canadian scientists discovered that louder noises can seriously hurt some animals． The research team found that powerful underwater explosions were causing whales in the area to lose their hearing． This seriously affected the whale's ability to exchange information and find their way． Some of the whales even died． The explosions had caused their ears to bleed．

    Many researchers whose work depends on ocean sounds disagree to a limit of one hundred and twenty decibels． They say such a limit would mean an end to important industrial and scientific research． Scientists do not know how much and what kinds of noises are harmful to ocean animals． However， many scientists think that noise is a greater danger than they believed．It's time for them to take action to help ocean animals．

（1）Which of the following is not caused by human beings？　　

A． The noise of industrial underwater explosions．

B． The noise of ocean drilling．

C． The sound of underwater earthquakes．

D． The noise of ship engines．

（2）What does the second paragraph mainly tell us？　　

A． The same noise measures differently on land and in the ocean．

B． Different places may have different types of noises．

C． The noises can cause humans to lose hearing．

D． There are different kinds of natural sounds in the ocean．

（3）Which of the following statements is TRUE？　　

A． Powerful underwater explosions aren't harmful to whales' ears．

B． Many researchers are against the noise limit of 120 decibels．

C． Noises cannot cause whales' death．

D． The noise limit of 120 decibels would hardly influence the industrial research．

（4）According to the passage ，we can infer that scientists will probably　　

A． work hard to cut down natural sounds

B． stop industrial and scientific research in oceans

C． try their best to make no noise

D． protect ocean animals from harmful noises