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名词解释题
土壤有机质平均停留时间 mean residence time of soil organic matter
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Organic Food:Why?1 Europe is now the biggest market for organic food in the world,expanding by 25 percent a year over the past 10 years.So what is the attraction of organic food for some people?The really important thing is that organic sounds more"natural".Eating organic is a way of defining oneself as natural,good,caring, different from the junk-food-eating masses.2 Unlike conventional farming,the organic approach means farming with natural,rather than man- made , fertilisers and pesticides. Techniques such as crop rotation（轮种）improve soil quality and helporganic farmers compensate for the absence of man-made chemicals.As a method of food production,organic is,however,inefficient in its use of labour and land;there are severe limits to how much food can be pro- duced.Also,the environmental benefits of not using artificial fertilisers are tiny compared with the amount of carbon dioxide emitted（排放）by transporting food.3 Organic farming is often claimed to be safer than conventional farming. Yet studies into organic farming worldwide continue to reject this claim.An extensive review by the UK Food Standards Agency foundthat there was no statistically significant difference between organic and conventional crops.Even where re-sults indicated there was evidence of a difference,the reviewers found no sign that these differences would have any noticeable effect on health.4 The simplistic claim that organic food is more nutritious than conventional food was always likely to be misleading. Food is a natural product,and the health value of different foods will vary for a number of rea-sons,including freshness,the way the food is cooked,the type of soil it is grown in,the amount of sunlight and rain crops have received,and so on.Likewise,the flavour of a carrot has less to do with whether it was fertilised with manure（粪便）or something out of a plastic sack than with the variety of carrot and how long ago it was dug up.5 The notion that organic food is safer than"normal"food is also contradicted by the fact that many of our most common foods are full of natural toxins（毒素）.As one research expert says : " People think that the more natural something is,the better it is for them.That is simply not the case.In fact,it is the opposite that is true:the closer a plant is to its natural state,the more likely it is that it will poison you.Naturally, many plants do not want to be eaten,so we have spent 10,000 years developing agriculture and breeding out harmful traits from crops."Techniques of organic farming help________.A:affect their nutritional contentB:poison youC:improve soil qualityD:be eatenE:show that organic crops are safer than conventional ones F: be specially trained
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共用题干
Organic Food:Why?1 Europe is now the biggest market for organic food in the world,expanding by 25 percent a year over the past 10 years.So what is the attraction of organic food for some people?The really important thing is that organic sounds more"natural".Eating organic is a way of defining oneself as natural,good,caring, different from the junk-food-eating masses.2 Unlike conventional farming,the organic approach means farming with natural,rather than man- made , fertilisers and pesticides. Techniques such as crop rotation（轮种）improve soil quality and help organic farmers compensate for the absence of man-made chemicals.As a method of food production,organic is,however,inefficient in its use of labour and land;there are severe limits to how much food can be pro- duced.Also,the environmental benefits of not using artificial fertilisers are tiny compared with the amount of carbon dioxide emitted（排放）by transporting food.3 Organic farming is often claimed to be safer than conventional farming. Yet studies into organic farming worldwide continue to reject this claim.An extensive review by the UK Food Standards Agency found that there was no statistically significant difference between organic and conventional crops.Even where re- sults indicated there was evidence of a difference,the reviewers found no sign that these differences wouldhave any noticeable effect on health.4 The simplistic claim that organic food is more nutritious than conventional food was always likely to be misleading. Food is a natural product,and the health value of different foods will vary for a number of rea- sons,including freshness,the way the food is cooked,the type of soil it is grown in,the amount of sunlight and rain crops have received,and so'on.Likewise,the flavour of a carrot has less to do with whether it was fertilised with manure（粪便）or something out of a plastic sack than with the variety of carrot and how long ago it was dug up.5 The notion that organic food is safer than"normal"food is also contradicted by the fact that many of our most common foods are full of natural toxins（毒素）.As one research expert says: "People think that the more natural something is,the better it is for them.That is simply not the case.In fact,it is the opposite that is true:the closer a plant is to its natural state,the more likely it is that it will poison you.Naturally, many plants do not want to be eaten,so we have spent 10,000 years developing agriculture and breeding out harmful traits from crops."Techniques of organic farming help_________.A:affect their nutritional contentB:poison youC:improve soil qualityD:be eatenE:show that organic crops are safer than conventional onesF:be soeciallv trained
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单选题MDT为平均停工时间（Mean Down Time），也称为平均延误时间（Mean Delay Time），它等于（）A
预防性时间+纠正性时间B
纠正性时间+等待时间C
纠正性时间+预防性时间+等待时间D
平均修理时间-平均间隔时间
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单选题The maximum difference between mean time and apparent time is （）.A
equal to the longitude expressed in time unitsB
about 16 minutesC
the difference between the GHA of mean sun and the first point of AriesD
15°of arc
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单选题MDT为平均停工时间(Mean Down Time)，也称为平均延误时间(Mean Delay Time)，它等于( )A
预防性维修时间＋纠正性维修时间B
纠正性时间＋等待时间C
纠正性维修时间＋预防性维修时间＋等待时间D
平均修理时问－平均间隔时间
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判断题通常使用平均修复时间MTTR（Mean Time to Repair）和平均故障间隔时间MTBF（Mean Time Between Failure）这两个指标来评价产品或系统的可靠性。A
对B
错
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单选题By using previous communication system, rescue is often a matter of chance. What does “a matter of chance” mean?（）A
occasionallyB
accidentallyC
oftenD
usually
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名词解释题土壤有机质半减期 half-life of soil organic matter
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