The job of a scientist is to find out the     1    （true）in the field of science. It is a     2    （challenge）profession. Scientists usually have to do thousands of     3    （experiment）in order to prove something.     4     they are often disappointed if they fail, most of them never give up. My next door neighbor is a scientist,     5     studies radiation.

He is always working in his lab,     6    （try）to figure out all the mysteries that make him     7    （puzzle）. When I met him the other day, he had just come back from work, looking excited. He told me he had had     8    breakthrough. He sounded so trilled. Then I noticed that he was wearing shoes that did not match. He must have been working     9    hard to notice! I think it's good to do a job that you are interested in. Otherwise you will get bored     10    （easy）.