完形填空

阅读下面短文，掌握其大意，然后从以下各题所给的四个选项(A、B、C和D)中，选出最佳选项。

　　Why is a space left between the rails of a railway line where one piece joins the next? The space 1 to let the rail expand when it gets 2 . On a hot day, the metal expands and if it 3 to do this, the mils would bend 4 shape. This caused railway 5 in the past.

　　 6 solids expand much less than liquids or gases, the 7 increases can add up to a lot, when there are long 8 of rail. For example, the difference in length of rail, in summer and winter, 9 the distance between London and Edinburgh, is about 1/4 mile.

　　We 10 keep in our minds and must not forget the expansion of metal when we build a very long mental bridge 11 . So spaces are left in the places 12 the mental is joined.

　　When 13 colder, it becomes smaller in size. We can make use of the 14 that solids expand when they are heated, and become smaller in size when they get colder and 15 they do it at different 16 .

　　For example, when an iron band has to fit tightly 17 a wooden wheel, first we make it 18 than the wheel, then we 19 it, so that it goes on easily. When it gets colder, it becomes smaller in size and 20 the wheel very tightly.

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Dye (染料) can bring a little color to life. Most clothing is colored with dyes. Modern, manufactured dyes can be costly. Natural dyes from plant and animal products have been used since ancient times. So this week, we describe a natural way to dye wool.
There are several methods to put dye onto material. The vat method, for example, can be used to dye wool with onionskins. For this example, use one hundred grams of natural wool. The wool must be clean. Leave it overnight in water and liquid soap. Then wash it with clean water that is a little warm. Gently squeeze out the extra water.
A solution called a mordant (媒染) is used in the dying process. A mordant helps fix the dye to the material. Traditionally, mordants were found in nature. Wool ash is one example. But chemical mordants such as alum are popular today. Alum is sold in many stores. It is often mixed with cream of tartar, a fine powder commonly used in cooking.
Mix eight grams of alum with seven grams of cream of tartar in a small amount of hot water. Add the solution to a metal pan of cool water. Next, add the wool and place the mixture over heat. Slowly bring the liquid to eighty-two degrees Celsius. Heat the mixture for forty-five minutes. After it cools, remove the wool and wash it.
To prepare the dye solution, cover thirty grams of onionskins with water. Use only the dry, brown outer skins. Boil the liquid until the onionskins lose their color, about forty-five minutes. Remove the skins after the dye cools.
Now it is time to dye the wool. Place the wool into the dye and heat the mixture. Bring it to a boil, then immediately reduce the heat to eighty-two degrees. Now heat the dye for about forty-five minutes or until the wool is the desired color. Keep in mind that wet wool looks darker than it is.
Once the dye cools, remove the wool and wash it. Now the wool is orange or yellow. Or at least it should be.
57. According to the passage, mordants are ________.
A. dyes used in the dying process
B. materials which will be put dye to
C. wood ashes used in the dying process
D. not dyes but play an important role in the dying process
58. Which of the following statements about “natural dyes” is true?
A. They might be cheaper than chemical dyes.
B. They are more expensive than chemical dyes.
C. They have been used for only recent years.
D. They are all made from animal products.
59. As for the vat method, which of the following statements is NOT necessarily needed?
A. Ash.                B. Water.           C. Mordant.              D. Temperature.
60. Choose the proper order of dying wool:
a. boil the liquid with onionskins.
b. add mordants to a metal pan of cool water.
c. wash the wool with clean water.
d. put the wool into the liquid and heat it
e. heat the mixture and then wash it.
A. c, b, e, a, d        B. e, b, c, d, a     C. b, e, a, d, c              D. a, b, e, c, d

Dye (染料) can bring a little color to life. Most clothing is colored with dyes. Modern, manufactured dyes can be costly. Natural dyes from plant and animal products have been used since ancient times. So this week, we describe a natural way to dye wool.

There are several methods to put dye onto material. The vat method, for example, can be used to dye wool with onionskins. For this example, use one hundred grams of natural wool. The wool must be clean. Leave it overnight in water and liquid soap. Then wash it with clean water that is a little warm. Gently squeeze out the extra water.

A solution called a mordant (媒染) is used in the dying process. A mordant helps fix the dye to the material. Traditionally, mordants were found in nature. Wool ash is one example. But chemical mordants such as alum are popular today. Alum is sold in many stores. It is often mixed with cream of tartar, a fine powder commonly used in cooking.

Mix eight grams of alum with seven grams of cream of tartar in a small amount of hot water. Add the solution to a metal pan of cool water. Next, add the wool and place the mixture over heat. Slowly bring the liquid to eighty-two degrees Celsius. Heat the mixture for forty-five minutes. After it cools, remove the wool and wash it.

To prepare the dye solution, cover thirty grams of onionskins with water. Use only the dry, brown outer skins. Boil the liquid until the onionskins lose their color, about forty-five minutes. Remove the skins after the dye cools.

Now it is time to dye the wool. Place the wool into the dye and heat the mixture. Bring it to a boil, then immediately reduce the heat to eighty-two degrees. Now heat the dye for about forty-five minutes or until the wool is the desired color. Keep in mind that wet wool looks darker than it is.

Once the dye cools, remove the wool and wash it. Now the wool is orange or yellow. Or at least it should be.

57. According to the passage, mordants are ________.

A. dyes used in the dying process

B. materials which will be put dye to

C. wood ashes used in the dying process

D. not dyes but play an important role in the dying process

58. Which of the following statements about “natural dyes” is true?

A. They might be cheaper than chemical dyes.

B. They are more expensive than chemical dyes.

C. They have been used for only recent years.

D. They are all made from animal products.

59. As for the vat method, which of the following statements is NOT necessarily needed?

A. Ash.                B. Water.           C. Mordant.              D. Temperature.

60. Choose the proper order of dying wool:

a. boil the liquid with onionskins.

b. add mordants to a metal pan of cool water.

c. wash the wool with clean water.

d. put the wool into the liquid and heat it

e. heat the mixture and then wash it.

A. c, b, e, a, d        B. e, b, c, d, a     C. b, e, a, d, c              D. a, b, e, c, d

    Dye (染料) can bring a little color to life. Most clothing is colored with dyes. Modern, manufactured dyes can be costly. Natural dyes from plant and animal products have been used since ancient times. So this week, we describe a natural way to dye wool.

    There are several methods to put dye onto material. The vat method, for example, can be used to dye wool with onionskins. For this example, use one hundred grams of natural wool. The wool must be clean. Leave it overnight in water and liquid soap. Then wash it with clean water that is a little warm. Gently squeeze out the extra water.

    A solution called a mordant (媒染) is used in the dying process. A mordant helps fix the dye to the material. Traditionally, mordants were found in nature. Wool ash is one example. But chemical mordants such as alum are popular today. Alum is sold in many stores. It is often mixed with cream of tartar, a fine powder commonly used in cooking.

    Mix eight grams of alum with seven grams of cream of tartar in a small amount of hot water. Add the solution to a metal pan of cool water. Next, add the wool and place the mixture over heat. Slowly bring the liquid to eighty-two degrees Celsius. Heat the mixture for forty-five minutes. After it cools, remove the wool and wash it.

    To prepare the dye solution, cover thirty grams of onionskins with water. Use only the dry, brown outer skins. Boil the liquid until the onionskins lose their color, about forty-five minutes. Remove the skins after the dye cools.

    Now it is time to dye the wool. Place the wool into the dye and heat the mixture. Bring it to a boil, then immediately reduce the heat to eighty-two degrees. Now heat the dye for about forty-five minutes or until the wool is the desired color. Keep in mind that wet wool looks darker than it is.

    Once the dye cools, remove the wool and wash it. Now the wool is orange or yellow. Or at least it should be.

1.According to the passage, mordants are ________.

A. dyes used in the dying process

B. materials which will be put dye to

C. wood ashes used in the dying process

D. not dyes but play an important role in the dying process

2.Which of the following statements about “natural dyes” is true?

A. They might be cheaper than chemical dyes.

B. They are more expensive than chemical dyes.

C. They have been used for only recent years.

D. They are all made from animal products.

3.As for the vat method, which of the following statements is NOT necessarily needed?

A. Ash.             B. Water.          C. Mordant.       D. Temperature.

4.Choose the proper order of dying wool:

a. boil the liquid with onionskins.

b. add mordants to a metal pan of cool water.

c. wash the wool with clean water.

d. put the wool into the liquid and heat it

e. heat the mixture and then wash it.

A. c, b, e, a, d     B. e, b, c, d, a     C. b, e, a, d, c       D. a, b, e, c, d

Dye (染料) can bring a little color to life. Most clothing is colored with dyes. Modern, manufactured dyes can be costly. Natural dyes from plant and animal products have been used since ancient times. So this week, we describe a natural way to dye wool.

         There are several methods to put dye onto material. The vat method, for example, can be used to dye wool with onionskins. For this example, use one hundred grams of natural wool. The wool must be clean. Leave it overnight in water and liquid soap. Then wash it with clean water that is a little warm. Gently squeeze out the extra water.

         A solution called a mordant (媒染) is used in the dying process. A mordant helps fix the dye to the material. Traditionally, mordants were found in nature. Wool ash is one example. But chemical mordants such as alum are popular today. Alum is sold in many stores. It is often mixed with cream of tartar, a fine powder commonly used in cooking.

         Mix eight grams of alum with seven grams of cream of tartar in a small amount of hot water. Add the solution to a metal pan of cool water. Next, add the wool and place the mixture over heat. Slowly bring the liquid to eighty-two degrees Celsius. Heat the mixture for forty-five minutes. After it cools, remove the wool and wash it.

         To prepare the dye solution, cover thirty grams of onionskins with water. Use only the dry, brown outer skins. Boil the liquid until the onionskins lose their color, about forty-five minutes. Remove the skins after the dye cools.

         Now it is time to dye the wool. Place the wool into the dye and heat the mixture. Bring it to a boil, then immediately reduce the heat to eighty-two degrees. Now heat the dye for about forty-five minutes or until the wool is the desired color. Keep in mind that wet wool looks darker than it is.

         Once the dye cools, remove the wool and wash it. Now the wool is orange or yellow. Or at least it should be.

57. According to the passage, mordants are ________.

A. dyes used in the dying process

B. materials which will be put dye to

C. wood ashes used in the dying process

D. not dyes but play an important role in the dying process

58. Which of the following statements about “natural dyes” is true?

A. They might be cheaper than chemical dyes.

B. They are more expensive than chemical dyes.

C. They have been used for only recent years.

D. They are all made from animal products.

59. As for the vat method, which of the following statements is NOT necessarily needed?

A. Ash.                      B. Water.              C. Mordant.                   D. Temperature.

60. Choose the proper order of dying wool:

a. boil the liquid with onionskins.

b. add mordants to a metal pan of cool water.

c. wash the wool with clean water.

d. put the wool into the liquid and heat it

e. heat the mixture and then wash it.

A. c, b, e, a, d            B. e, b, c, d, a     C. b, e, a, d, c            D. a, b, e, c, d