A pine(松树) tree in California was regarded as the oldest tree in the world. People thought it was nearly 5,000 years old, but they could not be true. Then someone cut the tree down with a chain saw(锯子). Killing the oldest tree down was a silly thing to do. But when the tree was cut down, everyone knew its age. It was 4,900 years old. How can you tell the age of a tree? If you ever see a tree that has just been cut down, take a look at the cut part. You will see rings. There are little rings in the middle. Around each ring is a larger ring is a larger ring. The ring near the bark(书皮) is the biggest one of all. Cunt these rings. A tree grows one ring each year. A 10-year-old tree has 10 rings. A 60- year-old tree has 60 rings. How many rings does a 4,900-year-old tree have?
( )1.The oldest tree stopped growing____.
A. because it was too old to grow B. after people climbing it
C. because it had grown too high D. when someone cut it down
( )2.If you want to know a tree’s age, you may ____.
A. count its rings B. take off its bark
C. cut it into pieces D. measure(测量)how round it is
( )3.A tree with 4,900 rings must be ____.
A. old enough to be cut down B. more than 5,000 years old
C. 4,900 years old D. smaller the ring near its bark is
( )4.The older a tree is, the ____.
A. more rings it has B. more rings it grows each year
C. fewer rings it has D. smaller the ring near its bark is
( )5.This story tells us how to____.
A. use a chain saw B. tell the age of a tree
C. find the biggest ring D. cut down an old pine tree
The world is not only hungry, but it is also thirsty for water. This may seem strange to you, since nearly 70% of the earth’s surface is covered with water. But about 97% of that is sea water, or salt water. Man can only drink and use the other 3%-the fresh water from rivers, lakes, underground, and other sources(资源). And we can not even use all of that. Even worse, some of it has been made dirty.
However, as things stand today, this fresh water is still enough for us. But our need for water is becoming larger and larger quickly-almost day by day. We should take steps to do with this problem now and in this way we can get away from a serious world-wide water shortage(缺少) later on.
We all have to learn how to stop wasting our valuable water. One of the first steps is to develop ways of reusing it. Today in most large cities, water is used only once and then sent out into a sewer system(下水道) .From there it returns to sea or runs into underground places.
But even if every large city reused its water, we still would not have enough. All we’d have to do to make use of sea water in the world is to remove the salt. If we take these steps we’ll be in no danger of drying up.
( )1.The world is thirsty for water because____.
A. man hasn’t got enough food to eat B. we haven’t got enough fresh water
C. only 70% of the earth’s surface is water D. more water is sent into sewer systems
( )2.The underlined word valuable means ____.
A. much and salty B. fresh and enough C. dear and useful D. clean and helpful
( )3.What should we do if we want to have enough fresh water?
Make full use of the sea water.
Carry salt water into lades or rivers.
Try to save the fresh water as much as possible.
Do our best to use the water again.
A. (c) and (e) B.(a) and (d) C. (a), (c) and (d) D. (b), (d) and (e)
( )4.The best but the most difficult way to solve the water problem of the world is to ____.
A. remove the salt from sea water B. make the water in cities clean
C. take water from underground D. make the need for water smaller
( )5.What’s the best title(标题)for this passage?
A. The Importance of the Water B. The World’s Water Problem
C. The Thirsty World D. Fresh Water and Sea Water