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Plastics would harm the environment if you were to burn them. ()
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Too much drinking would ______ his health.
A.do harm for
B.do harmful to
C.do harm to
D.do harmful for
Suppose the earth's temperature rose by 3 degrees, ______.
A.great harm would be done to mankind
B.the sea level would go by 10 centimetres
C.all the land in the world would be flooded
D.crops would be unable to grow on the earth
It can be concluded that______.
A.raising the world's temperature only a few degrees would not do much harm to life on earth
B.lowering the world' s temperature merely a few degrees would lead many major farming areas to disaster
C.almost no temperature variations have occurred over the past decade
D.the world's temperature will remain constant in the years to come
It can be inferred from the passage that______.
A.raising the world's temperature only a few degrees would not do much harm to life on the earth
B.almost no temperature variations have occurred over the past decade
C.lowering the world's temperature merely a few degrees would lead many major farming areas to disaster
D.the world temperature will remain constant in the years to come
That industry is based on biotechnology. At the moment, biotech's main uses are in medicine and agriculture. But its biggest long-term impact may be industrial. Here, it will diminish demand for oil by taking the cheapest raw materials imaginable, carbon dioxide and water, and using them to make fuel and plastics.
Plastics and fuels made in this way would have several advantages. They could accurately be called "renewables", since nothing is depleted to make them. They would be part of the natural carbon cycle, borrowing that element from the atmosphere for a few months, and returning it when they were burned or dumped. That means they could not possibly contribute to global warming. And they would be environmentally friendly in other ways. Bioplastics are biodegradable, since bacteria understand their chemistry and can therefore digest them. Biofuels, while not quite "zero emission" from the exhaust pipe (though a lot cleaner than petrol and diesel), would be cleaner overall even than the fuel-cell technology now being touted as an alternative to the internal-combustion engine. That is because making the hydrogen that fuel cells use is not an environmentally friendly process, and never will be—unless it, too, uses biotechnology.
All this will, in the end, depend on costs. But these do not look unfavourable. Already, the price of bioplastics overlaps the top end of the petroleum-based plastics market. Bulk production should bring prices 'down, particularly when the raw materials are free. Meanwhile, ethanol would be a lot easier to introduce than fuel cells. Existing engines will run on it with minor tweaking, so there is no need to change the way ears are made. And since, unlike hydrogen, it is a liquid, the fuel-distribution infrastructure would not need radical change.
The future could be green in ways that traditional environmentalists had not expected. Whether they will embrace that possibility, or stick to sack-cloth, remains to be seen.
According to the author, applying biotechnology to industry
A.has brought about sustainable development.
B.proves to be nothing but an imagination.
C.will deprive most people of modern comforts.
D.contributes to the environmentally sound development.
Peter: Molly, look at this. The newspaper says we should sort trash.
Molly: That would be great! I always hate it when people mixing all the trash together.
Peter: () Many communities have already done that.
Molly: Yeah. The benefits of sorting out trash are obvious.
Peter: For instance?
Molly: If trash is sorted, it can be transferred to factories instead of the disposal plant.
Peter: That makes sense. ()Molly: With trash separated, pollution caused by incineration can be avoided.
Peter: It is high time for us to sort out the trash. Trash is trash only when everything is mixed together. () they can be useful again.
Molly: () Things like paper, glass, and plastics can all be recycled. They can be reused.
Peter: Sorting is good. () If people have no idea how to sort their trash, they will still put all waste in the same bag.
Molly: You are right. People should be informed about how to do that in the first place. Moreover, sorting trash should be made easy for us. Otherwise, few people would bother to do it.
Peter: I hope everything goes smoothly!
Molly: I believe it will.
A. I couldn't agree more.
B. What else?
C. Once we separate and recycle them.
D. But I have a concern.
E. That is really a great advice.
The virus told each computer to make many copies of itself. Within a few minutes, all the computers' power was being used to make copies of the virus. The computer could do no other work. It finally slowed down greatly, or simply stopped working. Computer experts spent many days trying to destroy the virus in the computer system.
The experts agree the virus could have been much worse. They say it could have sent orders to destroy huge amounts of electronic information.
Many experts believe, the recent computer virus showed the need for better computer security (安全). But that is a problem. The affected system provides a free exchange (交换) of ideas and information among universities, private companies and government offices. Increasing security too much would destroy this exchange. It would slow progress on many important research projects.
Which of the following statements is true?
A.Many computers were attacked by a virus in the U. S.
B.Many computers attacked by a virus in the U.S. lost their information.
C.A computer virus can harm human body.
D.A computer virus can help the computer owner do many things.
Which ofthe following comparison is not correct?
A) Thermal conductivity: metal < plastics
B) Thermal expansion: metal > plastics
C) Density: metal > plastics
D) Thermal conductivity: metal > plastics
What main advantage do cellular plastics offer?
A.Reduced density B.Improved crystallinity
C.Greater density D.Improved strength