问题 单项选择题

减小散射线的办法中,错误的是

A.相对减小管电压
B.压迫被照体减小厚度
C.加大被照体-胶片距离
D.扩大照射野
E.安装多层遮线器

答案

参考答案:D

解析:缩小照射野,减少散射线的发生。

阅读理解

阅读理解。

      Nuclear energy has always been controversial. But since the tsunami and nuclear disaster in

Fukushima (Japan) last year the issue is back in the headlines. And the world is divided- some countries

are planning more nuclear plants, while others have promised to shut theirs down.

     After Fukushima, Germany decided to switch off all its nuclear plants by 2022. Switzerland and Italy

are also phasing out nuclear power. But France and the United States remain staunch supporters of

atomic energy. In fact, almost 80% of France's electricity comes from nuclear power, the highest

percentage in the world. And in the US, the Obama administration said it "continues to support the

expansion of nuclear power, despite the crisis in Japan."

     Nuclear supporters claim nuclear power can help the environment. Unlike fossil fuels, nuclear power

doesn't create greenhouse gases. So, pro-nuclear countries argue that nuclear power allows them to

generate energy without contributing to climate change. Britain's chief scientific adviser (John Beddington)

supports this view. He recently said that the world doesn't have the luxury of ignoring nuclear energy.

     Nuclear power is also relatively cheap. Renewable energy sources such as solar, hydro and wind

power may be clean, but they're expensive; and right now, they require a lot of investment. This higher

cost of using "green energy" is usually passed onto the consumer. So, while many people may prefer their

energy to come from a renewable source, not so many are prepared to pay higher energy bills. This is of

particular concern while the world economy is in such bad shape.

     The main argument against nuclear energy is that it isn't safe. For a start, nuclear waste is very difficult

to dispose of, and remains toxic to humans for thousands of years. And even before Fukushima, there

were several high-profile nuclear disasters. The most famous is probably the 1986 Chernobyl disaster, in

the Ukraine. The radiation from the meltdown spread all over Europe, affecting thousands.

     The nuclear energy issue is very complex. And it doesn't look like it'll be resolved anytime soon. As a

Japanese commentator recently said, "it's been a bad year for the 'nuclear village', but I don't think they're down and out yet." The battle continues.

1. What does the underlined word "this " refer to in paragraph 4?  

A. The fact that many people prefer to use the green energy sources while unwilling to pay higher bill.

B. The cost of using renewable sources

C. The fact that the nuclear power is cheaper.

D. The investment of renewable energy sources

2. In the 5th paragraph, the author takes the case of Chernobyl disaster in Ukraine to _______.

A. convince the reader that nuclear waste is difficult to get rid of.

B. explain that nuclear waste may remain harmful to humans for thousands of years.

C. persuade the world not to use nuclear energy.

D. support the idea that nuclear energy is not safe.

3.We can learn from the last paragraph that _______.  

A. the Japanese commentator is positive about the future of nuclear energy.

B. the nuclear energy issue will be soon settled.

C. a battle will break out in the future.

D. Japan is considering to build a nuclear village in the future.

4. What is the author's purpose of writing the passage? 

A. To highlight the danger of using nuclear energy.

B. To introduce some serious nuclear disasters.

C. To show the argument between nuclear supporters and protesters.

D. To give some advice on how to use nuclear energy safely.

填空题