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Professor Lee’s book will show you in other fields.
A. how it can be used B. when can it be used
C. where be used it D. which can be used it
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In many high schools，there are strict rules about using mobile phones. If your phone rings in class，for example，the teacher will be very angry.
Every mobile phone has a ringtone (铃声). It tells you that someone is calling you. Now，there is a ringtone called “mosquitotone (蚊子铃声)”. Using it，students can receive calls and text messages (短信) in class but the teacher will not realize what is happening. How?
Mosquitotone has a special sound. Only children and teenagers can hear it. As we get older，we are unable to hear some sounds with high frequencies (频率). As a result，a child or teenager can hear the mosquitotone ringtone, but it’s_inaudible_to someone 20 or older.
But sometimes，people over 20 can hear the ringtone. One British student’s phone uses mosquitotone. In class，the student’s phone rang. The 32yearold teacher looked at the student and became unhappy. “I heard that. You know the rule：no mobile phone in class.”
Not all the students are interested in mosquitotone. Jerry Jones，a high school student of 17，says，“Using mosquitotone too often is bad for our hearing. I may use it for pleasure，but not in class. It’s unfair to the teachers！”
What do parents think of mosquitotone？“I think it is perfect for places like movie theaters，” says Connie Neeson,44.“Think about it. Yon’re watching a film and someone’s mobile phone rings. Mosquitotone is good because many people don’t hear it. However，it also has a bad influence on their study if students use it in class.”
1.Mosquitotone works because ________.
A. it is very loud B. it has no sound
C. it has a beautiful sound D. it uses high frequencies
2.The under lined part “it’s_inaudible_to” means “________”．
A. it can’t be seen by B. it can’t be heard by
C. it isn’t popular with D. it isn’t healthy for
3.The 32yearold teacher felt unhappy because the student ________.
A. was late for class B. didn’t do his homework
C. couldn’t answer her question D. was using a mobile phone in class
4.Connie Neeson thinks that mosquitotone ________.
A. has no bad influence B. is unfair to the teachers
C. has its advantage and disadvantage D. can’t be used in any public place
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products, they give us shade, and the most important of all, they help to prevent droughts and floods.
In many parts of the world, however, people have not realized the importance of trees to us.
Two thousand years ago, a rich and powerful country cut down its trees to build its warships, with
which it gained itself an empire (帝国). It gained the empire, but without its trees, its soil became hard
and poor. When the empire fell into pieces, the home country found itself faced by floods and hunger.
Even when a government realizes the importance of forests, it is difficult for it to make villagers see
this. The villagers want wood to cook their food, and they can earn money by making things or selling
wood to the town people. They are usually too lazy or too careless to plant and look after new trees. So
unless the government does something to control, and also to educate the people, the forests will slowly
disappear.
B. they provide people with shade
C. they help to prevent droughts and floods
D. they can be used to build warships
B. it couldn't provide its people with enough money
C. it didn't ask people to plant many trees
D. its people couldn't make a living
B. The government should do something to protect the forests.
C. The empire became rich and strong with its powerful warships.
D. People often don't take good care of the new trees they have planted.
B. the villagers realize the importance of the forests
C. the government doesn't do something to control or to educate the people
D. the villagers don't cut trees down to make money
B. to tell the story of the empire two thousand years ago
C. to call on people to do something to protect forests
D. to tell the people to plant as many trees as possible
| 阅读短文，根据短文内容，从短文后的五个选项中选出能填入空白处的最佳选项。选项中有一项为多余选项。 | |
| Dr.Jack Todd is very interested in clean water . 1 ,so it's natural that he is to developer of a smal l and affordable system(系统)to clean wastewater,His "Living Machine" can clean wastewater in your home or in your business. 2 The wastewater goes into a big plastic tank where bacteria(细菌)start to break down the waste.A few days later after it is dealt with, the water is brought into a greenhouse filled with plants and fish. With the help of sunlight,the plants and animals remove more chemicals from the water,making it cleaner, Then the water can be reused for washing or bathing 3 but the water is clean enough for watering the flowing, washing the dog, or even for bathing or swimming. The advantage of this technology is that it is affordable and good for the environment. 4 It can help to use less fresh water, and it can help keep the water supply unpolluted. | |
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This is so familiar that there seems to be no need to ask the reason for it. Yet no one really understands why
flowers open and close like this at particular times. The process (过程) is not as simple as we might think, as
recent experiments have shown. In one study, flowers were kept in constant (连续的) darkness. We might
expect that the flowers, without any information about the time of day, did not open as they normally do. In
fact, they continued to open at their usual time. This suggests that they have some mysterious (神秘的) way
of knowing the time. Their sense of time does not depend on information from the outside world; it is, so to
speak, inside them, a kind of "inner clock".
This discovery (发现) may not seem to be very important. However, it was later found that not just
plants but also animals -including man -have this "inner clock" which controls the working of their bodies and
influences (影响) their activities. Men, then, are also influenced by this mysterious power. Whether we wish
it or not, it affects such things in our life as our need for sleep, our need for food.
In the past, this did not matter very much because people lived in natural condition. In the modern
world, things are different; now there are spacemen, airplane pilots and, in ordinary life, a lot of people who
have to work at night. It would be very useful, then, to know more about the "inner clock". Such ordinary
things as flowers might help us understand more about ourselves.
B. for their opening and closing, flowers do not need information from the outside world
C. flowers are influenced by weak light even when they are in a dark room
D. flowers can be used for telling the time
B. is only found in animals
C. has not been understood by far
D. has an effect on human life
B. we do not yet understand plants and animals well enough
C. the number of spacemen and airplane pilots is fast increasing
D. we should try to live more naturally than we do now
B. will not open any longer
C. will open as they do in natural conditions
D. will always remain in full blossom (开花)
B. All living things except man
C. Flowers are the only things in the world that
D. Neither animals nor plants