题目内容
A chemical works____ built there.
A.is to being | B.have been | C.were to | D.has been |
D
解析
Since ancient times, people have known about its ability to reduce pain and high body temperature. More than 2000 years ago, the Greek doctor Hippocrates advised his patients to chew on the bark and leaves of the willow.
The tree contains a chemical called salicin(柳醇). From salicin, researchers in the 1800s discovered how to make salicylic acid(酸). And in 1897, a chemist named Felix Hoffmann at Friedrich Bayer and Company in Germany created acetyl salicylic acid. Later it became the active substance in a new medicine that Bayer called aspirin. The "a" came from acetyl. The "spir" came from the spirea plant, which also produces salicin. And the "in" Well, that is a common way to end medicine names.
In 1982, a British scientist shared the Nobel Prize in Medicine in part for discovering how aspirin works. Sir John Vane found that aspirin blocks the body from making natural substances called prostaglandins(前列腺素).Prostaglandins have several effects on the body. Some cause pain and the expansion, or swelling( 肿瘤; 膨胀), of damaged tissue. Others protect the lining of the stomach and small intestine. Prostaglandins also make the heart, kidneys and blood vessels (血管)work well. But there is a problem. Aspirin works against all prostaglandins, good and bad. Scientists learned how aspirin interferes with an enzyme(酶). One form of this enzyme makes the prostaglandin that causes pain and swelling. Another form of the enzyme creates a protective effect. So aspirin can reduce pain and swelling in damaged tissues. But it can also harm the inside of the stomach and small intestine(肠).
【小题1】What sickness can the medicine from the willow deal with according to the passage?
A.Cold | B.Toothache | C.Cancer | D.Skin disease |
A.It results from pain. |
B.It prevents the lining of the stomach and small intestine. |
C.It causes blood vessels to work wrongly. |
D.It is sometimes good but sometimes bad. |
A.Aspirin can treat almost diseases. |
B.Aspirin can create the protective enzyme. |
C.Aspirin can harm the inside of the stomach and small intestine. |
D.Aspirin can protect the inside of the stomach and small intestine. |
The deadly earthquake and tsunami (海啸) that struck Japan on March 11 damaged two nuclear power stations. Officials are now working to prevent dangerous radiation from poisoning the air in the area surrounding the Fukushima Daiichi plant. The Japanese government has ordered people living within 12 and a half miles of the plant to evacuate, and asked those living 12 and a half to 20 miles away to stay indoors.
Nuclear power plants create energy using a chemical reaction that produces large amounts of heat. Reactors(反应堆)in Japan have many long, thin rods, called fuel rods(棒), which must be kept cool.
If the reactor’s fuel rods aren’t cooled, the reaction can burn out of control. That’s what happened at the two Japanese plants after the quake caused a power failure and the cooling systems malfunctioned(发生故障). This overheating could cause radiation to escape and sicken many people.
Japan’s 54 nuclear reactors are built to withstand the many small or moderate earthquakes the country faces each year. But Friday’s earthquake was one of the most severe earthquakes ever recorded.
People exposed to unsafe levels of radiation have a higher than normal risk of getting cancer. The Japanese government has been distributing potassium iodide(碘化钾)pills to people in the surrounding areas to protect those who may have come in contact with radiation from the power plant. The pills flood the body with healthy potassium iodide. The potassium iodide works to crowd out “bad” iodine in the body that may have been poisoned by radiation.
On Tuesday morning, 750 workers left the Fukushima Daiichi plant. However, 50 workers stayed behind to use sweater to cool the fuel rods. These dedicated employees are risking their own lives to save many others.
On Thursday, officials used helicopters, fire trucks, and water cannons to spray water on the reactors to cool the fuel rods. But it’s not clear whether these efforts were successful. Officials are now working on a power line to restore electricity to the plant. They hope this will help restart the plant’s cooling system and stop the fuel rods from leaking radiation.
1.The underlined word “evacuate” in Paragraph 1 probably means .
A.help |
B.rest |
C.stop |
D.leave |
2.What can we learn from the text?
A.The local people are scared and ready to run away. |
B.The earthquake led to many deaths and caused damage to roads. |
C.The Japanese government has found a kind of pill that can treat cancer. |
D.The two stations were damaged because their cooling systems didn’t work. |
3.In the last paragraph, the author mainly states .
A.lack of help |
B.international aids |
C.the government’s efforts |
D.the result of the disaster |
4.This text is most probably taken from .
A.a research paper |
B.a newspaper report |
C.a class presentation |
D.a chemistry textbook |