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【简答题】
The food we eat seems to have a great effect on our health. Although science has made big steps in making food more fit to eat, it has, at the same time, made many foods unfit to eat. Some research has shown that perhaps eighty percent of human illness is related to food and forty percent of cancer is related to food as well. That food is related to illness is not a new discovery. In 1945, some researchers realized that things commonly used to keep colour in meats and other food additives(添加剂)caused cancer. Yet, these additives remain in our food, and it is difficult to know which things on the wrappings(包装)of foods are helpful or harmful. The additives which we eat are not all so direct. Farmers often give penicillin to their animals, and because of this, penicillin has been found in the milk of cows. Sometimes similar tings are supplied to animals not for their health, but just to make a profit. The farmers are simply trying to fatten the animals in order to get a higher price on the market. Although some countries have tried to control such things, the practice continues. 小题1:Which of the following is not true? A.Some wrappings of food are harmful. B.Farmers try to make more money on the market by fattening their animals. C.“The practice continues” means “things are still going on like that”. D.We needn’t take care of what we eat. 小题2:According to this passage, we can know . A.perhaps most of human illness is caused by what we eat B.perhaps most kinds of cancer are related to what people eat C.cancer was discovered in 1945 D.science has made food unfit to eat 小题3:Things that are used to keep colours in meats are . A.harmful B.useless C.helpless D.dangerous 小题4:All the additives . A.are bright and colourless B.are not bright and colourful C.have indirect effects on our health D.have direct effects on our health
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参考答案:
举一反三
【单选题】发射机的输出功率是指()。
A.
射频放大器输出端的功率
B.
发射机送至天线输入端的功率
C.
天线辐射出去的功率
D.
由天线外部所测到的功率
【单选题】某交易者预测5月份大豆期货价格将上升,故买入50手,成交价格为4000元/吨。当价格升到4030元/吨时,买入30手;当价格升到4040元/吨时,买入20手;当价格升到4050元/吨时,买入10手。该交易者建仓的方法为()。
A.
平均买高策略
B.
平均买低策略
C.
金字塔式买入卖出策略
D.
以上均不对
【判断题】光纤通信系统的光发射机输出功率越大越好,可以使光中继段距离更长。()
A.
正确
B.
错误
【单选题】某交易者预测5月份大豆期货价格将上升,故买入5手,成交价格为3400元/吨.之后价格下跌,该交易者对市场趋势和判断保持不变,在价格跌到3390元/吨时。买入3手,当价格跌到3380元/吨时,买人2手,则该建仓方法为()。
A.
平均买高法
B.
倒金字塔式建仓
C.
金字塔式建仓
D.
平均买低法
【单选题】某投机者预测5 月份大豆期货合约价格将上升,故买入5 手(10 吨/手),成交价格为2015 元/吨,此后合约价格迅速上升到2025 元/吨;为进一步利用该价位的有利变动,该投机者再次买入4手5 月份合约;当价格上升到2030 元/吨时,又买入3 手合约;当市价上升到2040元/吨时,又买入2 手合约;当市价上升到2050元/吨时,再买入1手合约。后市场价格开始回落,跌到2035元/吨,该投机者立...
A.
-1305
B.
1305
C.
-2610
D.
2610
【简答题】发射机输出功率
【单选题】发射机的输出功率直接影响雷达的探测能力,通常规定()为发射机的输出功率。有时为了测量方便,也可以规定在指定负载上的功率为发射机的输出功率。
A.
发射机送至馈线系统的功率
B.
发射机送至收发开关的功率
C.
发射机送至天线输入端的功率
D.
发射机送至定向耦合器处的功率
【单选题】某交易者预测5月份大豆期货价格将上升,故买入5手,成交价格为3000元/吨;当价格升到3030元/吨时,买入3手;当价格升到3040元/吨时,买入2手;当价格升到3050元/吨时,买入1手。该交易者建仓的方法为( )。
A.
平均买低法
B.
倒金字塔式建仓
C.
平均买高法
D.
金字塔式建仓
【多选题】发射机的输出功率直接影响雷达的 和 。
A.
威力
B.
抗干扰能力
【简答题】有一调频发射机,用正弦波调制。未调制时,发射机在50 Ω电阻负载上的输出功率为Po=100 w。将发射机的频偏由零慢慢增大,当输出的第一个边频成分等于零时,即停止下来。试计算: 1)载频成分的平均功率; 2)所有边频成分总的平均功率; 3)第二边频成分总的平均功率。 注:J1(3.83)=0,J0(3.83)≈-0.4,J2(3.83)≈0.4。
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