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问题 单项选择题 A型题

高频探头的优点是可提供（）。

A.更高的分辨力

B.增大反射体的频移

C.提高侧向分辨力并且衰减降低

D.增强穿透力

E.聚焦能力增强

答案

参考答案：A

解析：高频探头的波长短，使纵向分辨力提高，但穿透力降低。

单项选择题

下列关于受益人的说法正确的是( )

A．受益人也有交纳保险费的义务
B．受益人与投保人可以是无血缘关系的人
C．受益人一般不可放弃受益权
D．无行为能力人不能成为受益人
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完形填空

Scientists have developed a non-stick chewing gum(口香糖). The new gum can   小题1: (remove) easily from pavements, shoes and clothes. It’s the result of polymer (聚合体) research at the University of Bristol and could be launched commercially in 2008.   小题2:  it catches on(流行), the product will solve  小题3:  major headache for present authorities around the world.

“A great 小题4:  (disadvantage) of our Clean Gum is that it is easy to remove and has the potential to be 小题5: (environment) degradable (可降解的),” said Terence Cosgrove, a professor of chemistry  小题6:  helped to found a company called Revolymer to commercialize the technology.

Today’s chewing gums are made  小题7:synthetic latex(人工制造的乳液), which is resistant to the weather and is strongly sticky. The new gum adds a special polymer to change its properties(特性),    小题8:  (make) it far less sticky.

In two street trials,   小题9:  commercial gums remained stuck to the pavement   小题10:    Clean Gum came away naturally in all cases.

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