What is the main idea of the article Cigars: Health Effects and Trends?

A．When it comes to cancer, cigars are not any safer than cigarettes.

B．Cigars may be addictive while cigarettes are not easily so.

C．Cigars contain less harmful substances than cigarettes.

D．Increase in cigar-smoking does not affect public health much.

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文章主旨题。倒数第三段中的一句话概括了文章的中心。即“…cigars are not safe altematives to cigarettes and may be addictive．”选项A意思与之相符。因此本题的正确答案为A选项。

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1 What is the doctors' advice to those cigar-smokers?

A．To give it up completely.

B．To give up part of it.

C．Not to think about it any more.

D．To cure the diseases first.

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2 In the context of this passage, "secondhand smoke" may mean __________.

A．smoking bad-quality cigars

B．smoking very cheap cigars

C．being near cigar smokers when they are not smoking

D．being near cigar smokers when they are smoking

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3 请根据短文的内容，回答题。

Batteries Built by Viruses

What do chicken pox, the common cold, the flu, and AIDS have in common? They're all disease caused by viruses, tiny microorganisms that can pass from person to person. It's no wonder that when most people think about viruses, finding ways to steer clear of viruses is what's on people's minds.
Not everyone runs from the tiny disease carriers, though. In Cambridge, Massachusetts,scientists have discovered that some viruses can be helpful in an unusual way. They are putting viruses to work, teaching them to build some of the world's smallest rechargeable batteries.
Viruses and batteries may seem like an unusual pair, but they're not so strange for engineer Angela Belcher, who first came up with5 the idea. At the Massachusetts Institute of Technology(MIT) in Cambridge, she and her collaborators bring together different areas of science in new ways. In the case of the virus-built batteries, the scientists combine what they know about biology,technology and production techniques.
Belcher's team includes Paula Hammond, who helps put together the tiny batteries, and Yet-Ming Chiang, an expert on how to store energy in the form of a battery. "We're working on things we traditionally don't associate with nature," says Hammond.
Many batteries are already pretty small. You can hold A, C and D batteries6 in your hand. The coin-like batteries that power watches are often smaller than a penny. However, every year, new electronic devices like personal music players or cell phones get smaller than the year before. As these devices shrink, ordinary bakeries won't be small enough to fit inside.
The ideal battery will store a lot of energy in a small package. Right now, Belcher's model battery, a metallic disk completely built by viruses, looks like a regular watch battery. But inside,its components are very small-so tiny you can only see them with a powerful microscope.
How small are these battery parts? To get some idea of the size, pluck one hair from your head.
Place your hair on a piece of white paper and try to see how wide your hair is-pretty thin, right?
Although the width of each person's hair is a bit different, you could probably fit about 10 of these virus-built battery parts, side to side, across one hair. These microbatteries may change the way we look at viruses7.
According to the first paragraph people try to __________.

A．kill microorganisms related to chicken pox, the flu, etc.

B．keep themselves away from viruses because they are invisible

C．stay away from viruses because they are causes of various diseases

D．cure themselves of virus-related diseases by taking medicines

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