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标题: xdf讲义题 [打印本页]

作者: xinglufree 时间: 2009-4-16 21:04
标题: xdf讲义题

it is crucial important to farmers that the herbicide they used to control weeds not damage their crops. one very effective herbicide is safe fot corn, but soybeans are damaged even by the herbicide's residue, which remains in the soil more than a year after the herbicide is applied. soybeans and corn are not sown together in the sameriled; nevertheless, most farmers are reluctant to use the herbicide on their own corn.

which of the following, if true, provides the strongest justification for the farmers' reluctance?

A the residue of the herbicide in the soil a year after application is not enough to control most weeds effectively.

B to maint ain the nutrients in the soil, corn and soybeans are often planted in a riled in an althernate year.

C the demand fot soybeans is growing faster than is the demand fot core.

D for maximum yield, soybean plants are grown closer together to each other than are corn plants.

E the application of herbicides is less crucial for soybean than forcorn crops.

The answer of this question is A. I chosed B

作者: h5641 时间: 2009-4-17 08:33
There is a trick in the given conditions from question. :-)

According to the question, all the concerns are about herbicide's residue remains in the soil would more than a year and soybeans could be damaged from that residue, that's why corn and soybean can not be sown together.

if soybean and corn can not be sown in the "same field"...then what mentioned above in the question about the residue would damage the soybean is trivial. (a noise)

Hence, the only thing had to be concerned is the "Effectiveness" on the corn its self.

Hope helps~

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