题目内容

They form a polar molecule, ____ is, ____ with a slightly positive end and a slightly negative end.


  1. A.
    which; that
  2. B.
    it; one
  3. C.
    that; one
  4. D.
    one; that
C
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完形填空（共20小题；每小题1.5分，满分30分）阅读下面短文，掌握其大意，然后从1—20题各题所给的四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项。

Throughout history man has had to accept the fact that all living things must die. But people now live longer than they   1  . Yet, all living things still show the   2   of aging, which will eventually   3  death.

Aging is not a disease, but as a person passes maturity (成熟期), the cells of the body and the  4 they form do not function as well as they  5  in childhood and teenage years. The body provides less  6   against disease and is more  7  to have accident.

A number of related causes may   8   aging. Some cells of the body have a fairly long life, but they are not   9 when they die. As a person ages,   10  of brain cells and muscle cells decreases.   11  body cells die and are replaced by new cells. In an aging person the   12  cells may not be as workable or as capable  13   growth as those of a young person.

Another  14   in aging may be changes within the cells  15  . Some of the protein chemicals in cells are known   16  with age and become less elastic (有弹性的). This is why the skin of old people wrinkles (皱纹) and   17 . This is also the reason why old people   18  in height. There may be other more important chemical changes in the cells. Some complex cell chemicals, such as DNA and RNA, store and   19  information that the cells need． Aging may affect this  20 and change the information-carrying molecules so that they do not transmit the information as well.

1. A．would                    B．be used to            C．used to               D． used

2. A．function              B．effect                                          C．affect             D． sign

3.    A．lead in             B．give in                 C．run into              D． result in

4.    A．hands             B．feet                    C．heart                 D． organs

5.    A．do                B．has done            C．did                   D． had done

6.    A．energy            B．protection          C．vigor              D． power

7.    A．likely              B．probable            C．possible              D． alike

8.    A．attend to           B．contribute to       C．add to               D． devote to

9.    A．replaced           B．reborn               C．recovered         D． surrendered

10. A．a number          B．the amount        C．the number        D． a great deal

11. A．The others        B．The other         C．Another            D． Other

12. A．old                B．left                 C．new               D． other

13. A．to                  B．for                 C．of                 D． in

14. A．factor              B．effect               C．reason              D． element

15. A．for themselves    B．of themselves   C．themselves       D． on their own

16.   A．change              B．to have changed  C．to change         D． to be changed

17. A．hangs loose       B．hangs loosely       C．is hanging loosely D． is hanging loose

18. A．increase            B．shrink               C．lengthen            D． decrease

19. A．pass away         B．pass by             C．pass off            D． pass on

20. A．improvement      B．procession         C．approach          D． process

Astronomers have captured(捕获) the first direct image of a planet being born.

Adam Kraus, of the University of Hawaii’s Institute for Astronomy, said the planet is being formed out of dust and gas circling a 2-million-yea-old star about 450 light years from Earth.

The planet itself, based on scientific models of how planets form, is believed to have started taking shape about 50,000 to 100,000 years ago.

Called LkCa 15b, it’s the youngest planet ever observed. The previous record holder was about five times older.

Kraus and his colleague, Michael Ireland from Macquarie University and the Australian Astronomical Observatory, used Keck telescopes on Mauna Kea(a volcano on the island of Hawaii, US) to find the planet. Kraus presented the discovery Wednesday at NASA’s Goddard Space Flight Center in Maryland.

Observing planets while they’re forming can help scientists answer questions like weather planets form early in the life of a star or later, and whether they form relatively close to stars or father away.

Planets can change orbits(轨道) after forming, so it’s difficult to answer such questions by studying older planets.

“These very basic questions of when and where are best answered when you can actually see the planet forming, as the process is happening right now,” Kraus said.

Scientists hadn’t been able to see such young planets before because the stars they’re circling around outshine(光亮强过) them. Kraus and Ireland used two techniques to overcome this problem.

One method, which is also used by other astronomers, was to change the shape of the telescope mirrors to remove light distortion(扭曲) created by the Earth’s atmosphere. The other method they used, which was unique, was to put masks with several holes over most of the telescope mirrors. The combination of these techniques allowed the astronomers to obtain high-quality images that let them see the planet next to the bright star.

The star LkCa 15—the planet is named after its star—was the team’s second target. They immediately knew they were seeing something new, so they plan to gather more data on the star.

1.The research on younger planets helps scientists _____________.

A. study why planets change orbits after forming

B. understand how planets move around their stars

C. answer questions about the age of stars and planets

D. know the relationship between planets and their stars

2.Why are young planets like LkCa 15b hard to discover?

A. Their stars are brighter than them..      B. They are very far from the earth.

C. They are generally too small.           D. They rarely form.

3.According to the text, Kraus and Ireland _____________.

A. have been working in the same university

B. observed the planet on a volcano in Hawaii

C. used two new methods in the observation

D. cut holes in the mirrors when observing

4.Which of the following would be the best title for the text?

A. Youngest planet seen as it’s forming.

B. Planet 450 light years away discovered.

C. World’s first direct image of a planet taken.

D. New technique helps discover young planets.

 

Astronomers have captured(捕获) the first direct image of a planet being born.

Adam Kraus, of the University of Hawaii’s Institute for Astronomy, said the planet is being formed out of dust and gas circling a 2-million-yea-old star about 450 light years from Earth.

The planet itself, based on scientific models of how planets form, is believed to have started taking shape about 50,000 to 100,000 years ago.

Called LkCa 15b, it’s the youngest planet ever observed. The previous record holder was about five times older.

Kraus and his colleague, Michael Ireland from Macquarie University and the Australian Astronomical Observatory, used Keck telescopes on Mauna Kea(a volcano on the island of Hawaii, US) to find the planet. Kraus presented the discovery Wednesday at NASA’s Goddard Space Flight Center in Maryland.

Observing planets while they’re forming can help scientists answer questions like weather planets form early in the life of a star or later, and whether they form relatively close to stars or father away.

Planets can change orbits(轨道) after forming, so it’s difficult to answer such questions by studying older planets.

“These very basic questions of when and where are best answered when you can actually see the planet forming, as the process is happening right now,” Kraus said.

Scientists hadn’t been able to see such young planets before because the stars they’re circling around outshine(光亮强过) them. Kraus and Ireland used two techniques to overcome this problem.

One method, which is also used by other astronomers, was to change the shape of the telescope mirrors to remove light distortion(扭曲) created by the Earth’s atmosphere. The other method they used, which was unique, was to put masks with several holes over most of the telescope mirrors. The combination of these techniques allowed the astronomers to obtain high-quality images that let them see the planet next to the bright star.

The star LkCa 15—the planet is named after its star—was the team’s second target. They immediately knew they were seeing something new, so they plan to gather more data on the star.

1.The research on younger planets helps scientists _____________.

A. study why planets change orbits after forming

B. understand how planets move around their stars

C. answer questions about the age of stars and planets

D. know the relationship between planets and their stars

2.Why are young planets like LkCa 15b hard to discover?

A. Their stars are brighter than them..      B. They are very far from the earth.

C. They are generally too small.           D. They rarely form.

3.According to the text, Kraus and Ireland _____________.

A. have been working in the same university

B. observed the planet on a volcano in Hawaii

C. used two new methods in the observation

D. cut holes in the mirrors when observing

4.Which of the following would be the best title for the text?

A. Youngest planet seen as it’s forming.

B. Planet 450 light years away discovered.

C. World’s first direct image of a planet taken.

D. New technique helps discover young planets.

 

The opening of the Sherlock Holmes Museum to the public on March 27, 1990, was an event that should have happened several decades ago. Baker Street is, after all, one of the world’s most famous streets because of its long association with the great detective.

Thousands of people all over the world write to Sherlock Holmes, they form clubs and societies in his honor, and they celebrate his anniversaries. Now it is also possible to see where and how he lived in Victorian times!

Here visitors will recognize familiar objects mentioned in the stories. You can take as many photographs as you want (the maid will be pleased to assist) and when you are ready to leave, a ride home in a horse-drawn carriage will complete your 19th century experience!

Sherlock Holmes and Doctor Watson lived at 221b Baker Street from about 1881 to 1904. Apartment 221b was on the first floor of a lodging house, which they rented from a Mrs Hudson. The famous study that Holmes and his friend Dr Watson shared for almost 25 years is on the first floor overlooking Baker Street.

We know from Doctor Watson’s descriptions that their sitting room overlooking Baker Street was “illuminated(照明、照亮) by two broad windows” and that it was quite small.

Doctor Watson’s bedroom was on the second floor next to Mrs Hudson’s room and it overlooked an open yard at the back of the house. These rooms are used today for exhibits, where center stage is taken by a magnificant bronze bust(半身像)of Mr Holmes. Visitors can browse through literature, paintings, photographs and newspapers of the period. Memorabilia（纪念品） from the adventures and a selection of letters written to and from Mr Holmes are also on display.

The museum’s large and attractive souvenir shop is located on the ground floor. Here you will find a unique collection of gifts, objects of art, figures, busts, prints, books, playing cards, T-shirts, －novelties of every description available exclusively to museum visitors.

1.According to the article, we can conclude that Sherlock Holmes’ admirers      .

A．expect replies from him

B．made the opening of the museum possible

C．treat him as if he were a real person

D．often adapt his books into films or plays

2.Which of the following is TRUE?

A．The sitting room is small but has two big windows.

B．Mrs Hudson’s rooms are not used as exhibit rooms.

C．Mr Holmes’ and Dr Watson’s bedrooms are on the same floor.

D．Mr Holmes and Mrs Hudson shared ownership of Apartment 221b Baker Street.

3.When in the museum, which of the following can visitors not do?

A．Take photos of the rooms or objects on show

B．Buy unusual and interesting souvenirs

C．Learn some news of Mr Holmes’s times

D．Ask the maid to serve you tea in the Victorian times

 

How much rain has fallen on the earth in the past? Man has not always kept weather records. Because scientists need a way to learn about past rainfall, they study the tree rings.

A tree’s trunk (树干) keeps growing year by year. Under its bark (树皮), a tree adds a layer of new wood each year it lives. If you look at a tree stump, you can see the layers. They are called annual ring (年轮).

On some trees, all of the rings are of the same width. But the ponderosa(美国黄松) that grows in the American southwest have rings in different withes. The soil in he southwest is dry. The pines depend on rainfall for water. In a year of good rainfall, they form wide rings. In a dry year, they form narrow ones.

Scientists do not have to cut down a pine to study its rings. With a special tool, they remove a narrow piece of wood from the trunk without harming the tree. Then they look at the width of each ring to see how much rain fell in the year it formed.

Some pines are hundreds of years old and have hundreds of rings. These rings are from an annual record o0f past rainfall in the southwest.

1.We could infer from the passage that ______.

A．a tree grows faster when it has a lot of water

B．scientists cut down trees to study tree rings

C．pine trees form rings of he same width every year

D．the ponderosa grows in he southeast

2.A tree grows a new layer of wood _____.

A．each week

B．whenever it rains

C．every year

D．every season

3.On the whole, the passage is about _____.

A．why the tree trunks grow bigger

B．why scientists study tree rings

C．trees that lived hundreds of years ago

D．the ponderosa in the US

4.The scientists _____ to know how much rain fell in a certain area in the past.

A．climbed up the tree

B．moved the pine tree

C．removed a piece of wood

D．studied the width of the tree rings

5.Which of he following is true according to the passage?

A．Young trees have fewer annual rings than old one.

B．The trunk of a tree never changes in size.

C．Trees in the southwest do not need rain.

D．Soil in the southwest is fit for the growth of trees.

 

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