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1.The flow of electrons is from the negative zinc plate to the positive copper plate.

2.High precision implies a high degree of exactness but with no implication as to accuracy.

3.Electrode potential depends on the concentration of the ions.

4.The determination of trace concentrations of mercury in minerals is described.

5.A concentration process is important now that the depletion of high grade ores is a possibility.

6.The ancient people counted with stones.

7.As oil is found deep in the ground,its presence cannot be determined by a study of the surface.

8.Today the electronic computer is widely used in solving mathematical problems having to do with weather forecasting and putting satellites into orbit.

9.If there were no attraction,the electron would fly away from the proton in a straight line.

10.In case of an oil-pump failure,the moving parts will become overheated.

B.将下列词语翻译成中文。

（II）篇章翻译练习

The world population has topped 6 billion people and is predicted to double in the next 50 years.Ensuring an adequate food supply for this booming population is going to be a major challenge in the years to come.GM foods promise to meet this need in a number of ways:

Crop losses from insect pests can be staggering,resulting in devastating financial loss for farmers and starvation in developing countries.Farmers typically use many tons of chemical pesticides annually.Consumers do not wish to eat food that has been treated with pesticides because of potential health hazards,and run-off of agricultural wastes from excessive use of pesticides and fertilizers can poison the water supply and cause harm to the environment.Growing GM foods such as B.t.corn can help eliminate the application of chemical pesticides and reduce the cost of bringing a crop to market.

For some crops,it is not cost-effective to remove weeds by physical means such as tilling,so farmers will often spray large quantities of different herbicides (weed-killer) to destroy weeds,a time-consuming and expensive process,that requires care so that the herbicide doesn’t harm the crop plant or the environment.Crop plants genetically-engineered to be resistant to one very powerful herbicide could help prevent environmental damage by reducing the amount of herbicides needed.For example,Monsanto has created a strain of soybeans genetically modified to be not affected by their herbicide product Roundup.A farmer grows these soybeans which then only require one application of weed-killer instead of multiple applications,reducing production cost and limiting the dangers of agricultural waste run-off.

There are many viruses,fungi and bacteria that cause plant diseases.Plant biologists are working to create plants with genetically-engineered resistance to these diseases.

Unexpected frost can destroy sensitive seedlings.An antifreeze gene from cold water fish has been introduced into plants such as tobacco and potato.With this antifreeze gene,these plants are able to tolerate cold temperatures that normally would kill unmodified seedlings.

Drought tolerance/salinity tolerance

As the world population grows and more land is utilized for housing instead of food production,farmers will need to grow crops in locations previously unsuited for plant cultivation.Creating plants that can withstand long periods of drought or high salt content in soil and groundwater will help people to grow crops in formerly inhospitable places.

Malnutrition is common in third world countries where impoverished peoples rely on a single crop such as rice for the main staple of their diet.However,rice does not contain adequate amounts of all necessary nutrients to prevent malnutrition.If rice could be genetically engineered to contain additional vitamins and minerals,nutrient deficiencies could be alleviated.For example,blindness due to vitamin A deficiency is a common problem in third world countries.Researchers at the Swiss Federal Institute of Technology Institute for Plant Sciences have created a strain of “golden” rice containing an unusually high content of betacarotene (vitamin A).Since this rice was funded by the Rockefeller Foundation,a non-profit organization,the Institute hopes to offer the golden rice seed free to any third world country that requests it.Plans were underway to develop a “golden” rice that also has increased iron content.However,the grant that funded the creation of these two rice strains was not renewed,perhaps because of the vigorous anti-GM food protesting in Europe,and so this nutritionallyenhanced rice may not come to market at all.

Medicines and vaccines often are costly to produce and sometimes require special storage conditions not readily available in third world countries.Researchers are working to develop edible vaccines in tomatoes and potatoes.These vaccines will be much easier to ship,store and administer than traditional injectable vaccines.

Not all GM plants are grown as crops.Soil and groundwater pollution continues to be a problem in all parts of the world.Plants such as poplar trees have been genetically engineered to clean up heavy metal pollution from contaminated soil.(736 words)