Questions （1）to（5） are based on the following passage:What makes a person a scientist？

Questions （1）to（5） are based on the following passage:

What makes a person a scientist？ Does he have ways ---or tools ---of learning that are different from those of others？ The answer is no. It is not the tools a scientist uses but how he uses these tools that makes him a scientist. You will probably agree that knowing how to use a power saw is important to a carpenter. You will probably agree, too, that knowing how to investigate, how to discover information, is important to everyone. The scientist, however, goes one step further: he must be sure that he has a reasonable answer to his question and that his answer can be confirmed by other persons. He also works to fit the answers he gets to many questions into a large set of ideas about how the world works

The scientist’s knowledge must be exact. There is no room for half right or right just half the time. He must be as nearly right as the condition permit. What works under one set of conditions at one time mustwork under the same conditions at other times. If the conditions are different, any changes the scientist observes in a demonstration must be explained by the changes in the conditions. This is one reason that investigations are important in science. Albert Einstein, who developed the theory of relativity, arrived at this theory through mathematics. The accuracy of his mathematics was latter tested through investigation. Einstein’s ideas were shown to be correct. A scientist uses many tools for measurement. Then the measurements are used to make mathematical calculations that may test his investigations.

（1）A sound scientific theory should be one that .

A) works under one set of conditions at one time and also works under the same conditions at other times

B) leaves no room for improvement

C) does not allow any change even under different conditions

D) can be used for many purposes

（2）What, according to the passage, makes a scientist？

A) The tools he uses.

B) His ways of learning.

C) The way he uses his tools.

D) The various tools he uses.

（3） Albert Einstein built up his theory of relativity through .

A) investigation

B) experiments

C) tests

D) mathematics

（4）“…Knowing how to investigate, how to discover information, is important to everyone.” The author says this to show .

A) the importance of information

B) the importance of thinking

C) the difference between scientists and ordinary people

D) the difference between carpenters and ordinary people

（5） What is the main idea of the passage？

A) Scientists are different from ordinary people.

B) The theory of relativity.

C) Exactness is the core of science.

D) Exactness and way of using tools are the key to the making of a scientist.