Cloud seeding is a method of artificially causing clouds to produce precipitation （降水） in the form of rain or snow．Cloud seeding has also been used in attempts to modify the severity of hail storms and hurricanes．The effectiveness of cloud seeding remains controversial （有争议的）．but it continues to be used in some regions to try to increase rainfall for agriculture and to build snow packs for water supplies and power production．

Cloud seeding was developed by American scientists Irving Langmuir and Vincent Joseph Schaefer during and after World War II．Their work began as an effort to learn more about the buildup of ice on airplane wings, and eventually led them to attempt to create rainfall by releasing several pounds of crushed frozen carbon dioxide into a cloud from an airplane．In this form, the carbon dioxide is called dry ice．On November 13, 1946, the technique appeared to produce snow directly under the cloud; the snow then turned to rain as it fell to the ground．

For their experiment, Langmuir and Schaefer selected a supercooled cloud, one in which the water droplets remain liquid in subfreezing temperatures．Their theory was that small grains of dry ice falling through the cloud would cause tiny droplets of water vapor in the cloud to freeze into crystals that attracted more water vapor．Their theory proved to be correct and eventually the crystals became heavy enough to fall from the cloud as snow．As the snow reached the warmer temperatures closer to the ground, it melted and became rain．

Another scientist, Bernard Vonnegut, produced a method of cloud seeding using silver iodide （碘化银）．He used particles of silver iodide because its crystal structure resembled that of ice in clouds．Silver

iodide also had practical advantages over frozen carbon dioxide It could be stored at room temperature

and did not require an airplane as a delivery mechanism．Instead, silver iodide crystals could be fired by

cannons （大炮） high into the air, where wind carried them into the clouds．

1.According to the text, Langmuir and Schaefer had intended to deal with__

A．how to freeze carbon dioxide??????????????????????

B．how to remove ice on plane wings

C．how to make weather forecast for the war?????????????

D how to hide planes in clouds at war

2.What is the CORRECT order of the course for cloud seeding with dry ice?

a．snow becoming rain in wanner temperatures???????????? b．crystals attracting more water vapor

c．crystals falling in the form of snow???????????????????? d．crystals becoming very heavy

e．freezing tiny droplets of water vapor into crystals

f．putting small grains of dry ice in the cloud

A．a-c-f-d-b-e??????????????? ????????????? B．b-f-e-a-c-d????????????

C．f-e-b-d-c-a??????? ????????????? D．e-a-d-c-b-f

3.Bernard chose silver iodide as a method of cloud seeding because___．

A．it is much cheaper than dry ice?????? ????????????? B．it can be stored at any rooms

C．it can be sent into clouds by wind?? ????????????? D．it is similar

4.The best title for the passage may be "____"．

A．Cloud Seeding?????? ?????????????

B．Artificial Raining???????

C．Weather Changing

D．Cloud Gathering

5.How many methods of cloud seeding are mentioned in the passage?

A．three ????????????? B．two?????? ????????????? C．one????????????? D.four

71.   _________________ the advertisement, he decided to buy the house.

72.   Although he didn’t mention any names at the meeting, everyone knew who he was __________.

73.   He had a good ___________ English so he got a job in an international company easily.

74.   He has been ____________ becoming a scientist.

75.   You can keep the book _____________you return it to me tomorrow.

I sometimes wonder if old Finchley has the right personality to be a research scientist. He keeps asking when he’ll be coming back. After all, it was his own fault. Nobody tries out what has just been invented on themselves any more but Finchley. Well, he must have pumped about a thousand cc into himself before I noticed he was clearly becoming smaller.
It was funny watching him, because his clothes remained the same in size. They simply piled up around him so that he looked like a small boy in his father’s clothes. But he kept getting smaller and smaller. As my colleague Dawson and I watched him, he disappeared! All we could see was Finchley’s clothes on the floor. They looked so strange, because the lab coat was on top, shirt and trousers inside and, I suppose, underclothes inside again. It gave me a strange feeling, and I think Dawson was a bit shaken, too.
Dawson was sitting on his chair in front of a microscope he’d been using to examine a family of mites(螨). He looked through the scope kind of absently again, and was nearly scared to lose awareness when he found old Finchley waving back from the other end.
It seems as if Finchley had taken a free ride on a dust mite and landed on the land of the mite family. Of course, we didn’t know till Finchley told us later. But anyhow, as I said, Dawson nearly passed out. He jumped off his chair and pointed at the microscope, too shocked to speak.
【小题1】It can be inferred that Finchley, Dawson and the writer have possible invented      .

I sometimes wonder if old Finchley has the right personality to be a research scientist. He keeps asking when he’ll be coming back. After all, it was his own fault. Nobody tries out what has just been invented on themselves any more but Finchley. Well, he must have pumped about a thousand cc into himself before I noticed he was clearly becoming smaller.

It was funny watching him, because his clothes remained the same in size. They simply piled up around him so that he looked like a small boy in his father’s clothes. But he kept getting smaller and smaller. As my colleague Dawson and I watched him, he disappeared! All we could see was Finchley’s clothes on the floor. They looked so strange, because the lab coat was on top, shirt and trousers inside and, I suppose, underclothes inside again. It gave me a strange feeling, and I think Dawson was a bit shaken, too.

Dawson was sitting on his chair in front of a microscope he’d been using to examine a family of mites(螨). He looked through the scope kind of absently again, and was nearly scared to lose awareness when he found old Finchley waving back from the other end.

It seems as if Finchley had taken a free ride on a dust mite and landed on the land of the mite family. Of course, we didn’t know till Finchley told us later. But anyhow, as I said, Dawson nearly passed out. He jumped off his chair and pointed at the microscope, too shocked to speak.

1.It can be inferred that Finchley, Dawson and the writer have possible invented      .

A．a machine to make people small            B．a new way to study the family of mites

C．a new powerful microscope               D．some kind of medicine

2.Finchley disappeared because      .

A．he tried out what has just invented on himself

B．his father’s clothes totally covered him up

C．he took something poisonous

D．he was changed into a dust mite

3.It can probably be concluded that Finchley       .

A．will remain tiny all the time                B．is a devoted scientist

C．is not fit to be a scientist                  D．passed out there and then

4.It frightened Dawson to see Fincley         .

A．got out of his scope by accident            B．was waving through his scope

C．suddenly got lost in his clothes             D．gradually disappeared in the lad

I sometimes wonder if old Finchley has the right personality to be a research scientist. He keeps asking when he’ll be coming back. After all, it was his own fault. Nobody tries out what has just been invented on themselves any more but Finchley. Well, he must have pumped about a thousand cc into himself before I noticed he was clearly becoming smaller.
It was funny watching him, because his clothes remained the same in size. They simply piled up around him so that he looked like a small boy in his father’s clothes. But he kept getting smaller and smaller. As my colleague Dawson and I watched him, he disappeared! All we could see was Finchley’s clothes on the floor. They looked so strange, because the lab coat was on top, shirt and trousers inside and, I suppose, underclothes inside again. It gave me a strange feeling, and I think Dawson was a bit shaken, too.
Dawson was sitting on his chair in front of a microscope he’d been using to examine a family of mites(螨). He looked through the scope kind of absently again, and was nearly scared to lose awareness when he found old Finchley waving back from the other end.
It seems as if Finchley had taken a free ride on a dust mite and landed on the land of the mite family. Of course, we didn’t know till Finchley told us later. But anyhow, as I said, Dawson nearly passed out. He jumped off his chair and pointed at the microscope, too shocked to speak

1. 1.

   It can be inferred that Finchley, Dawson and the writer have possible invented      

   1. A.
      a machine to make people small
   2. B.
      a new way to study the family of mites
   3. C.
      a new powerful microscope
   4. D.
      some kind of medicine
2. 2.

   Finchley disappeared because      

   1. A.
      he tried out what has just invented on himself
   2. B.
      his father’s clothes totally covered him up
   3. C.
      he took something poisonous
   4. D.
      he was changed into a dust mite
3. 3.

   It can probably be concluded that Finchley       

   1. A.
      will remain tiny all the time
   2. B.
      is a devoted scientist
   3. C.
      is not fit to be a scientist
   4. D.
      passed out there and then
4. 4.

   It frightened Dawson to see Fincley         

   1. A.
      got out of his scope by accident
   2. B.
      was waving through his scope
   3. C.
      suddenly got lost in his clothes
   4. D.
      gradually disappeared in the lad