Passage Three

　　Eating in space is different from eating on earth. The food that astronauts carry with them does not look like the food you eat. Some food is carried in closed bags. It is cooked and frozen before the astronauts get it. All the water is removed from the food. In the spaceship the astronaut puts the water back. He “shoots” hot or cold water into the food bag with a special gun. He eats the food through a small hole in the bag.

　　Other foods come in bite sizes. The astronaut puts a whole piece in his mouth at once. There an be no crambs. Crambs would float around the spaceship and get in the way. Meat and cake often come in bite-sized pieces. Astronauts can’t drink water from open cups. The water would float in drops in the air. The water is put in the special gun. The astronaut shoots the water into his mouth. Eating in space is not easy. Astronauts must learn to eat this way.

　　71. Some space foods are carried in _______.

　　A. water guns B. lunch boxes C. closed bags D. crumbs

　　72. The story does not say this, but from what we have read, we can tell that ______.

　　you get much hungrier in space than you do

　　you can’t have water to drink in a spaceship

　　astronauts must learn many new and different things

　　you can’t eat anything in a spaceship

　　73. Why can’t astronauts drink water from cups?

　　The water would come from the open cups.

　　The water would spill all over their food.

　　Crambs would float in the cups.

　　The cups would float in the air.

　　74. The main idea of the whole story is that _______.

　　there is more food and water in space than on earth

　　eating and drinking in space is a special problem

　　astronauts can never eat or drink in a spaceship

　　there is no food or water in a spaceship

　　75. Which of the following does the story lead you to believe?

　　Food for astronauts must be made in a special way.

　　All meat on earth comes in bite-sized pieces.

　　Astronauts will only eat cakes made from crambs.

　　Astronauts have to go hungry in a spaceship.

　　Passage Four

　　The energy which the sun radiates goes in every direction, and only a minute part of it falls on the earth. Even so, it represents power of about 5,000,000 horsepower (马力) per square mile per day; the sun gives us as much energy every miunte as mankind utilizes in a year. At present, we use this energy indirectly, and it is our final source of power. Coal represents the chemical action of the sun on green plants thousands of years ago. Water power results from the rain formed by vapor which comes from the evaporation of water under the sunshine. Even windmills operate because of air currents set in motion by the different heating affects of the sun in different places. Some day, through chemistry or some type of solar engine, we shall harness this great source of energy more directly. Already a scientist has worked out an engine, surprisingly efficient, in which the sun’s rays are concentrated through mirrors on a tube of water to create steam.

　　76. How much energy given off by the sun reaches the earth?

　　A. 100% but indirectly. B. 5%.

　　C. 50%. D. only a very tiny amount.

　　77. The reason why all the solar energy falling on the earth can’t be utilized is that ______.

　　only a very small part is available the sun is too distant from the earth

　　it takes thousands of years for this energy to be stored up in coal and oil

　　our scientific knowledge is not sufficient

　　78. Which of the following statements is NOT true?

　　Even windmill’s action depends on the sun.

　　The sun produces enormous energy for man to make use of.

　　Some day man will be able to utilize 100% of the solar energy that gets to the earth.

　　The sun produces different heating effects in different places.

　　79. In order to support this argument, the writer gives the example that _______.

　　a machine using solar energy efficiently has already been developed

　　the sun is our final source of power

　　man uses only a tiny part of the sun’s energy

　　the part of the sun’s energy we use is used indirectly

　　80. This passage centers mainly on ________.

　　harnessing energy through chemistry

　　our last source of power

　　how water power is produced

　　the amount of solar energy that can be utilized