In some countries in which there is very little rain at any time, the farmers have to irrigate their fields. Irrigation is easy enough if there is a great river near the crops, and if there is plenty of water in it. Canals carry the river water to the fields when necessary. In some seasons there may be too much water in the river, and the water may flood all the land near it. At other times the river water may not be enough for all the farmers, and then it will be difficult to irrigate the fields.
To prevent these difficulties, a dam may be built across the river. This will store water for dry seasons, and in wet seasons it will prevent the flooding of the land. A great lake will, no doubt, be formed behind the dam, and this may mean that houses and fields will be covered with water. Most people will accept that and will be ready to move to other places. Then the country can have the right amount of water at all times; more crops will be grown, there will be more food for everyone, and there will be no more floods.
Dams have been built for centuries in different parts of the world. Modern dame are usually built of concrete（混凝土）but earth dams were used in India and Sri Lanka about 2500 years ago. There was another across the River Tigris very long ago, and large numbers of irrigation canals were made in Iraq to irrigate the land. The Romans were great dam-builders and there was also a famous dam at Ma’ rubin Arabia.
We cannot use sea water for irrigation; the salt will not allow the crops to grow. Fresh water is always needed, and it is very difficult and costly to make fresh water from sea water. This is done in a few countries, but the fresh water is for drinking. There is not enough at present for irrigation. Perhaps a scientist will one day invent a cheaper way of producing fresh water from the sea.
【小题1】The first paragraph mainly talks about         .

   In some countries in which there is very little rain at any time, the farmers have to irrigate their fields. Irrigation is easy enough if there is a great river near the crops, and if there is plenty of water in it. Canals carry the river water to the fields when necessary. In some seasons there may be too much water in the river, and the water may flood all the land near it. At other times the river water may not be enough for all the farmers, and then it will be difficult to irrigate the fields.

   To prevent these difficulties, a dam may be built across the river. This will store water for dry seasons, and in wet seasons it will prevent the flooding of the land. A great lake will, no doubt, be formed behind the dam, and this may mean that houses and fields will be covered with water. Most people will accept that and will be ready to move to other places. Then the country can have the right amount of water at all times; more crops will be grown, there will be more food for everyone, and there will be no more floods.

   Dams have been built for centuries in different parts of the world. Modern dame are usually built of concrete（混凝土）but earth dams were used in India and Sri Lanka about 2500 years ago. There was another across the River Tigris very long ago, and large numbers of irrigation canals were made in Iraq to irrigate the land. The Romans were great dam-builders and there was also a famous dam at Ma’ rubin Arabia.

   We cannot use sea water for irrigation; the salt will not allow the crops to grow. Fresh water is always needed, and it is very difficult and costly to make fresh water from sea water. This is done in a few countries, but the fresh water is for drinking. There is not enough at present for irrigation. Perhaps a scientist will one day invent a cheaper way of producing fresh water from the sea.

1．The first paragraph mainly talks about          .

      A．the problems caused by river water      

       B．the necessity to irrigate the field

      C．the water shortage in some countries    

       D．the canals carrying water to fields

2．A dam is usually built          .

      A．to cover the houses and fields              

B．for people to have the right amount of water at all times

      C．to grow crops better

      D．to form a large lake

3．The underlined word“that”means         .

      A．a dam will be built across the river        

       B．a dam will store water for dry seasons

      C．in wet seasons a dam will prevent the flooding of the land

      D．houses and fields will be covered will water

4．The third paragraph suggests that         .

      A．modern dams are made of concrete      

       B．Romans once built many great dams

      C．there was too much water in 1rap in the past

D．modern dams are better than early dams

In some countries in which there is very little rain at any time, the farmers have to irrigate their fields. Irrigation is easy enough if there is a great river near the crops, and if there is plenty of water in it. Canals carry the river water to the fields when necessary. In some seasons there may be too much water in the river, and the water may flood all the land near it. At other times the river water may not be enough for all the farmers, and then it will be difficult to irrigate the fields.
To prevent these difficulties, a dam may be built across the river. This will store water for dry seasons, and in wet seasons it will prevent the flooding of the land. A great lake will, no doubt, be formed behind the dam, and this may mean that houses and fields will be covered with water. Most people will accept that and will be ready to move to other places. Then the country can have the right amount of water at all times; more crops will be grown, there will be more food for everyone, and there will be no more floods.
Dams have been built for centuries in different parts of the world. Modern dame are usually built of concrete（混凝土）but earth dams were used in India and Sri Lanka about 2500 years ago. There was another across the River Tigris very long ago, and large numbers of irrigation canals were made in Iraq to irrigate the land. The Romans were great dam-builders and there was also a famous dam at Ma’ rubin Arabia.
We cannot use sea water for irrigation; the salt will not allow the crops to grow. Fresh water is always needed, and it is very difficult and costly to make fresh water from sea water. This is done in a few countries, but the fresh water is for drinking. There is not enough at present for irrigation. Perhaps a scientist will one day invent a cheaper way of producing fresh water from the sea

1. 1.

   The first paragraph mainly talks about         

   1. A.
      the problems caused by river water
   2. B.
      the necessity to irrigate the field
   3. C.
      the water shortage in some countries
   4. D.
      the canals carrying water to fields
2. 2.

   A dam is usually built         

   1. A.
      to cover the houses and fields
   2. B.
      for people to have the right amount of water at all times
   3. C.
      to grow crops better
   4. D.
      to form a large lake
3. 3.

   The underlined word“that”means        

   1. A.
      a dam will be built across the river
   2. B.
      a dam will store water for dry seasons
   3. C.
      in wet seasons a dam will prevent the flooding of the land
   4. D.
      houses and fields will be covered will water
4. 4.

   The third paragraph suggests that        

   1. A.
      modern dams are made of concrete
   2. B.
      Romans once built many great dams
   3. C.
      there was too much water in 1rap in the past
   4. D.
      modern dams are better than early dams

The geographical location of a country and its physical characteristics are very important to its development and progress. he United States is very fortunate in this respect.

First of all, it has a good climate. In almost all sections of the country it is possible to live comfortably during the whole year. It is true that in the south it sometimes gets very hot, and in the north very cold. But the people who live in these regions become accustomed to the climate and never suffer very much when the weather is either very hot or very cold.

In a large country there is usually a great variety of different physical characteristics. In the United States, there are wide plains and high mountains, thousands of lakes and rivets of all sizes, cool forests and hot deserts, and a coastline several thousand miles long.

The many lakes and rivers, as well as the long coastline, have been of great importance to the development of the country, since they made possible the easy transportation of people and all the things people need. Transportation by water is still necessary and important. In modern times, however, trains, automobiles, trucks and airplanes are doing much of the work which was formerly done by ships and boats.

44．What are the principal physical characteristics of the United States？

A．Almost the same．  B．Rather various．

C．Very good for farming． D．Suitable for transportation．

45．In what respect is the United States very fortunate？

A．Geographical location．  B．Good climate．

C．Physical characteristics．       D．Both A and C．

46．Why are rivers，lakes and coastlines important to the development of the U. S. A？

A．They make the climate better．

B．They provide people with a good many opportunities of employment．

C．They provide people with good transportation and whatever they need．

D．They make the scenery of the country more beautiful and attractive．

47．What was used for transportation in the distant past in the U. S. A. ?

A．Trains．   B．Trucks．

C．Planes．   D．Ships and boats．

We all know that theme parks are places to have fun and amuse ourselves, but among so many exciting rides there are also some dangers, Make sure you know what the safety standards are for all the attractions at the park. If you do that , you will be safe and have fun.

    Drink water. Believe it or not , dehydration-- when your body doesn’t have enough water--is the commonest cause of injuries at theme parks. Drinking water while you are at the park is not enough.You must make sure that you drink enough water before your visit.

    Use your “common sense”. There are lots of people around , so make sure where your friends or family are .Also ,if you are walking and want to stop , make sure nobody is walking behind you. First step aside,then look behind and if you aren’t in anybody’s way,then stop.It might sound exaggerated(夸张的),but crashes between people can cause accidents.

    Follow the instructions. The majority of theme parks have instructions for each ride. Some rides only allow people of a certain height. So make sure you are not too tall or too short before boarding any ride. Also, people with certain diseases or conditions are advised not to go on some rides. Do remember : If you are told not to go on a ride, then DON’T.

  Do not ride with a bad atomach or if you’ve just eaten. Rides can make you ill because of their violent changes of direction and your lunch may end up on someone else’s head: surely not a very pleasant experience.

   Have fun, relax, and be a little brave!

Some rides might look scary but theme parks are very safe places.

1.What is the leading reason for injuries at theme parks?

A. Snow   B. Dehydration  C. Fire     D.Crashes

2.According to the author,____.

A. it doesn’t pay to go to theme parks       

B. people can have lots of fun in theme parks

C. men are more interested in theme parks than women

D. shy people should not go to theme parks

3.Which of the following will the author accept?

A. Children should not  play in theme parks.

B. One shouldn’t eat anything before riding.

C. One must always stay with his friends or family in theme parks.

D. One must read the instructions before playing in theme parks.