[概括大意]Radar is now a familiar tool. Like many others it was an unexpected discovery. It was first observed by two researchers， who were studying sound communication. They were sending signals from a station on one side of a river in Washington D to a vehicle across the river. They discovered that their signals were stopped by passing ships. They recognized the importance of this discovery at once.
The main idea of this paragraph is__________.
A.Study of Radar
B.Radar is now a familiar tool
C.Radar Working Principles
D.Radar was Discovered by Chance
[阅读理解]During work Tom always thought of the girl and felt as if he had met her somewhere， but he couldn‘t remember when. Tom concluded that the girl was in love with him and he was very excited. This girl maybe looked not as beautiful as the girl he had dated the other day， but she had a grand(豪华的)car. She must be very rich. So he chose to love this girl. When his work was over， Tom called the girl who had dated him. He said， “After several days’ thinking， I think I am not suited for being your boyfriend， so I hope you will forget me.”
We can learn from this passage that Tom ________.
A.was very poor
B.didn‘t like the biscuits
C.walked to work every morning
D.compared the two girls carefully
答案解析：答案选D。A、B、C三个选项所表达的内容均无法在文中找到根据，从This girl maybe looked not as beautiful as the girl he had dated the other day, but she had a grand(豪华的)car可以看出，Tom对两个女孩的样貌以及经济能力都在心里做了比较，D项正确。
[阅读理解]“Longer life would give us a chance to recover from our mistakes and promote long term thinking，” says Dr Gregory Stock of the University Of California School Of Public Health. “It would also raise productivity by adding to the year we can work.”
Longer lives don‘t just affect the people who live them. They also affect society as a whole. “We have war， poverty， all sorts of issues around， and I don’t think any of them would be at all helped by having people live longer，” says US bioethicist Daniel Callahan. “The question is ‘What will we get as a society’s suspect it won‘t be a better society.”
Which of the following is NOT mentioned as one of the things that living longer might enable an individual to do
A.Spending more time with his family.
B.Having more education.
C.Realizing more dreams.