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单项选择题

A．They may lose their ability to produce offspring.B．Th……

What happens to those insects when not killed by the spray of insecticide

A．They may lose their ability to produce offspring.
B．They may have a higher ability to adapt to the environment.
C．They move to other fields free from insecticide.
D．They never eat again those plants containing insecticide.

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单项选择题What can be inferred from the first paragraph

A．GM foods are particularly good to the kwashiorkor patients.
B．We cannot recognize the benefits of GM foods too early.
C．GM foods may have both benefits and harm.
D．GM foods may bring about great benefits to humans.

单项选择题The author cited the case of the pollen-sprayed milkweed leaves in Paragraph 3 to show______.

A．GM foods may harm crops
B．GM foods contain more protein
C．GM foods can kill insects effectively
D．GM foods also have a dark side

单项选择题Which of the following statements concerning banning GM foods is true according to the passage

A．Underdeveloped countries have banned GM foods.
B．Both Europe and the U.S. have banned GM foods.
C．Most European countries have not banned GM foods.
D．The United States has not banned GM foods.

单项选择题We can learn from the first paragraph that _____________.

A．the collapse of the cotton industry and increased demand in the Northern for labor caused the Great Migration
B．the black workers were used to urban living quite well
C．wages were pretty low in northern cities
D．the black workers in the North earned less than they did in south with the development of the mechanization

单项选择题Which of the following records has been a source of information in the author's investigation

A．United States Immigration Service reports from 1914 to 1930.
B．Payrolls of southern manufacturing firms between 1910 and 1930.
C．The Volume of cotton exports between 1898 and 1910.
D．The federal census of 1910.

单项选择题It can be inferred from the passage that easy conclusion (Para. 3 ) is based on the assumptions that

A．people who migrate from rural areas to large cities usually do so for economic reasons
B．most people who leave rural areas to take jobs in cities return to rural areas as soon as it is financially possible for them to do so
C．people with rural backgrounds are less likely to succeed economically in cities than are those with urban backgrounds
D．most people who were once skilled workers are not willing to work as unskilled workers

单项选择题According to the passage, which of the following is true of wages in southern cities in 1910

A．They were being pushed lower as a result of increased competition.
B．They had begun to rise so that southern industry could attract rural workers.
C．They had increased in large southern cities but decreased in small southern cities.
D．They had increased in newly developed industries but decreased in the older trades.

单项选择题The primary purpose of the passage is to __________.

A．argue that a discarded theory deserves new attention
B．present evidence that resolves a contradiction
C．introduce a recently discovered source of information
D．challenge a widely accepted explanation

单项选择题According to Harris Miller, __________.

A．many countries in the world are short of IT workers
B．IT workers are essential to the industrial revolution
C．IT workers are essential to the development of today' s society
D．iron ore is as important as IT workers in the course of social development

单项选择题According to the passage, who can get H-1B visas

A．Those who want to go to the U. S. A for further study.
B．Those who want to immigrate to the U. S. A.
C．Those with a university degree and want to work in the U. S. A for a' certain period.
D．Those who want to travel in the U. S. A.