转基因作物同普通植物的区别只是多了能使它产生额外特性的基因。早在1983年,生物学家

题型:单项选择题

问题:

转基因作物同普通植物的区别只是多了能使它产生额外特性的基因。早在1983年,生物学家就已经知道了怎样通过生物工程技术将外来基因移植到某种植物的脱氧核糖核酸中去,以便使它产生靠杂交方式根本无法获得的某种新的特性:抗除莠剂的特性、抗植物病毒的特性、抗某种害虫的特性等。用以移植的基因可来自任何生命体:细菌、病毒、昆虫等。转基因作物目前在世界上已种植有1000万公顷左右,种植最多的是棉花、玉米和西红柿等。在实验室试种的还有莴苣、西瓜、稻谷等品种。试验的目的除了增产之外,还在于提高这些品种的抗病毒能力。但同时也有专家担心转基因作物可能对环境有危险。比如在美国栽种的那种能抗虫害的玉米和棉花,可能加快出现一些更难对付的害虫.这类作物的所有分子都分泌出一些微量的“杀虫药”,一种像任何一种农药一样能选择杀死某些害虫的“雾剂”。尤其是那些能抗除莠剂的作物,它们一旦同野生状态下的“表姐妹”杂交之后,那些“表姐妹”也就会因此而成为除莠剂无法除掉的变种了。对于这种技术,尽管还有些问题需要继续研究,但这确是人类9000年作物栽培史上一场空前的革命。

下列说法符合原文意思的一项是()

A.转基因作物的研究已取得突破性进展,目前所有品种都得到推广种植

B.提高作物抗病毒的能力仍然是转基因技术研究没有完全解决的问题

C.更难对付的害虫的加快出现将是转基因作物给环境带来的最大危险

D.增产并不是转基因技术研究的目的,提高抗病毒能力是研究者最感兴趣的

考点:国家公务员行政职业能力测试行政职业能力测试
题型:单项选择题

水生软体动物完成气体交换的结构是                      (   )

A.鳃

B.肺

C.外套膜

D.入水管和出水管

题型:单项选择题

Some researchers claim that people’s personalities can be classified by their blood types

If you have blood type O, you are a leader. When you see something you want , you strive to achieve your goal. You are passionate, loyal, and  self-confident, and you are often a trendsetter(标新立异的人)。Your enthusiasm for projects and goals spreads to others who happily follow you. When you want something ,you may be ruthless(不留情面的)about getting it or blind to how your actions affect others .

Aother blood type A, is a social , “people” person . You like people and work well with them . Y ou are sensitive , patient , compassionate , and affectionate .You are a good peacekeeper because you want everyone to be happy .In a team situation , you resolve conflicts and keep things on a smooth course . Sometimes type As are stubborn and find it difficult to relax. They may also find it uncomfortable to do things alone.

People with type B blood are usually individualist who like to do things on their own . You may be creative and adaptable, and you usually say exactly what you mean . Also you can adapt to situations , you may choose to do so because of your strong independent streak. You may prefer working on your own to being part of a team .

The final blood is type AB . If you have AB blood , you are a natural entertainer. You draw people to you because of your charm and easy-going nature .ABs are usually calm and controlled , tactful(圆滑的) fair. On the downside ,though , they may take too long to make decisions. And they may procrastinate, putting off tasks until the last minute.

小题1:People with type O will do the following things except__________

A.manage businesses

B.self-control

C.be considerate

D.set the fasion小题2:Which of the following is not the feature of type A?

A.Stubborn

B.Sensitive

C.reserved

D.Patient小题3:The best profession for a type AB is __________

A.athlete

B.peacekeeper

C.actor

D.country leader

题型:单项选择题

“(二战前)苏联的工业已经迅速向前发展,因为政府提取了大约40%的国民收入用于再投资;相比之下,美国只提取了大约20%的国民收入。”材料强调的是

A.战时 * * 主义政策的有效性

B.新经济政策提高了人民的积极性

C.二战前苏联的体制促进了工业化进程

D.国民收入水平低是苏联解体的原因

题型:单项选择题

下列关于窗台的说法正确的是()。

A.悬挑窗台挑出的尺寸不应小于80mm

B.悬挑窗台常用砖砌或采用预制钢筋混凝土

C.当墙体厚度在370mm以上时,一般将窗下墙体内凹

D.外窗台的作用主要是排除下部雨水

E.外窗台应向外形成一定坡度

题型:单项选择题

某投资者以700元的价格买入某企业发行面额为1000元的5年期贴现债券,持有3年后试图以8%的持有期收益率将其卖出,则卖出价格应为()元。

A.816.48

B.881.80

C.857.34

D.793.83

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