Sagan believes that before the earth's resources are compleetely exhausted it will be possible to change the atmophere of Venus and so create a new world almost as large as earth itself. The difficult is that Venus is much hotter than the earth and there is only a tiny amount of water there.
Sagan proposes that algae organisms that can live in extremely hot or cold atmospheres and at the same time produce oxygen,should be bred in condition similar to those on Venus.As soon as this has been done, the algae will be placed in small rockets. Spaceship will then fly to Venus and fire the rockets into the atmosphere .In a fairly short time, the alge will break down the carbon dioxide into oxygen and carbon.
When the algae have done theri work, the atmosphere will become cooler,but befor man can set foot on Venus it will be neccessary for the oxygen to produce rain. The surface of the planet will still be too hot for man to land on it but the rain will eventually fall and in a few years something like earth will be reproduced on Venus.
1.Inte long run, the most insoluble problem caused by population growth on earth will probably be the lack of ______.
a.food b.oil c.space d.resources
2.Carl Sagan believes that Venus might be colonized from earth because _____
a.it might be possible to change its atmosphere
b.its atmosphere is the same as the earth's
c.there is a good supply of water on Venus
d.the days on Venus are long enough
3.On Venus there is a lot of ________.
a.water b.carbon dioxide c.carbon monoxide d.oxygen
4.Algae are plants that can____.
a.live in very hot temperatures b.live in very cold temperatures
c.manufacture oxygen d.all of the above
5. Man can land on Venus only when_______.
a.the algae have done their work b.the atmosphere becomes cooler
c.thereis oxygen d.it rains there
答案：cabdd
The United States is on the verge of losing its leading place in the world's technology. So says more than one study in recent years. One of the reasons for this decline is the parallel decline in the number of U.S. scientists and engineers.
Since 1976,employment of scientists and engineers is up 85 percent. This trend is expected to continue. However, the trend shows that the number of 22-year-olds--the near term source of future PH.D.s-is declining. Further adding to the problem is the increased competition for these candidates from other fields-law,medicine,business,etc. While the number of U.S. PH.D.s in science and engineering declines,the award of PH.D.s to foreign nationals is increasing rapidly.
Our inability to motivate students to pursue science and engineering careers at the graduate level is compounded because of the intense demand industry has for bright Bachelor's and Master's degree holders. Too often, promising PH.D.candidates, confronting the cost and financial sacrifice of pursuing their education,find the attraction of industry irresistible.
1.The U.S.will come to lose its leading place in technology probably because ________.
a. the number of PH.D. degree holders is declining
b. the number of scientists and engineers is decreasing
c. the number of 22-year-ilds is declining
d. scientists and engineers are not employed
2.The field of science and engineering is facing a competition from ________ .
a. technology b. foreign nationals
c. such fields as law, medicine and business d. postgraduates
3.Large-scale enterprises now need _______.
a. bright graduates and postgraduates b. new inventions
c. advanced technology d. engineers
4.Many promising postgraduates are unwilling to pursue a PH.D. degree because _________.
a. they are not encouraged to be engaged in science
b. industry does not require PH.D. holders
c. they have financial difficulties
d. they will spend much time and energy completing PH.D.
5.PH.D. candidates "find the attraction of industry irresistible" means that _________.
a. they find industry is attracting more and more college students
b. they don't think they can prevent themselves from working for industry
c. they cannot resist any attraction from all sides
d. they cannot work for industry any longer
答案：bcadb
There are three kinds of goals: short-term,medium-range and long-term goals.
Short-range goals are those that usually deal with current activities,which we can apply on a daily basis.Such goals can be achieved in a week or less,or two weeks,or possible months.It should be remembered that just as a building is no stronger than its foundation ,out long-term goals cannot amount to very munch without the achievement of solid short-term goals.Upon completing our short-term goals,we should date the occasion and then add new short-term goals that will build on those that have been completed.
The intermediate goals bukld on the foundation of the short-range goals.They might deal with just one term of school or the entire school year,or they could even extend for several years.Any time you move a step at a time,you should never allow yourself to become discouraged or overwhelmed. As you complete each step,you will enforce the belief in your ability to grow adn succeed.And as your list of completion dates grow,your motivation and desire will increase.
Long-range goals may be related to our dreams of the future. They might cover five years or more. Life is not a static thing.We should never allow a long-term goal to limit us or our course of action.
1.Our long-term goals mean a lot__.
a.if we complete our short-range goals
b.if we cannot reach solid short-term goals
c.if we write down the dates
d.if we put forward some plans
2.New short-term goals are bulid upon__.
a.two years
b.long-term goals
c.current activities
d.the goals that have been completed
3.When we complete each step of our goals ,__.
a.we will win final success
b.we are overwhelmed
c.we should build up confidence of success
d.we should strong desire for setting new goals
4.Once our goals are drawn up,__.
a.we should stick to them until we complete them
b.we may change our goals as we have new ideas and opportunities
c.we had better wait for the exciting news of success
d.we have made great decision
5.It is implied but not stated in the passage that ___.
a.those who habe long-term goals will succeed
b.writing down the dates may discourage you
c.the goal is only a guide for us to reach our desination
d.every should have a goal
答案：adcbc
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