It must have taken a great prehistoric thinker to imagine two thin slices of log connected， at their centers by a string stick. This would roll along just as the logs did， yet be much lighter and easier to handle. Thus the wheel and axle came into being and with them the first carts.

　　66. The wheel is important because _______.

　　A. it was man‘s first real invention B. all transportation depends on it

　　C. every machine depends on it D. both B and C

　　67. The wheel is called _______.

　　A. simple B. complicated C. strange D. unusual

　　68. It was remarkable of man to invent the wheel because _______.

　　A. it led to many other inventions B. man had no use for it then

　　C. there were no wheels in nature D. all of the above

　　69. The wheel was probably invented by ______.

　　A. a group of early hunters B. the first men on earth

　　C. a great prehistoric thinker D. the man who made the first cart

　　70. This selection says that the first wheel may have been a ______.

　　A. round piece of stone B. heavy log C. piece of metal D. slice of log

　　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.