阅读理解。

     When the world was very young, people lived only in hot places. They did not live in cold places because

they could not keep warm there.

     At first men did not know how to make a fire. Sometimes trees were hit by lightning. Then a fire was

started. People took some of the fire near their homes. A fire was very important for three reasons. It kept

them warm. Wild animals were frightened when they saw it. And when food was cooked, it tasted much

better.

     But men did not know how to make a fire. When they had a fire, they did not let it stop burning. If it went

out (熄灭), they could not start it again. They had to wait for lightning to start another fire. Sometimes they

had to wait for years.

     Later, they learned how to make a fire. But it was not easy to make something burn.

     Now we have matches. We can carry them in our pockets and make a fire when we want to.

1. "When the world was very young" means "          ".[ ]

A. before liberation (解放)

B. in the following years

C. before long

D. millions of years ago

2. People found that           .  [ ]

A. the cooked food tasted better than the uncooked food

B. the uncooked food tasted much better than the cooked food

C. wild animals enjoyed the cooked food

D. wild animals kept warm near the trees

3. People didn't let a fire stop burning because           . [ ]

A. they were not able to make a fire

B. they liked to wait for lightning

C. it rained now and then

D. they didn't like to make a fire

4. Now we can make a fire           .[ ]

A. by lightning

B. if it is necessary

C. for three reasons

D. in our pockets

5. Which of the following sentences is TRUE? [ ]

A. People are much cleverer now than they were long ago.

B. People were ready to let a fire go out.

C. People didn't want to make a fire because they were foolish. (愚蠢)

D. People stayed together with wild animals all the time.