题目内容
（请给出正确答案）
Scientists will()new methods of increasing the world's food supply
A、set aside
B、go over
C、turn up
D、come up with
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更多“Scientists will（)new methods o…”相关的问题
A.A.true
B.B.false
A.stick to
B.come up with
C.carry out
D.lead to
A.lead to
B.come up with
C.carry out
D.stick to
A. find
B. to be found
C. to find
D. found
Ultimately, the new study should help scientists to_____.
A．lower water levels
B．change their opinions
C．better predict climate change
D．bury sea-level cities like Dhaka and Shanghai
A、used to.
B、applied to.
C、suited to.
D、accustomed to.
Which of the following is true of Livingston？ ______
A．He thinks he has discovered a new possibility in the link between sun spots and the weather on the Earth.
B．He has great doubts about the theory that the sun's frequent changes have an influence on the Earth's climate.
C．He has been recently informed by other scientists of the possibility that more sun spots will appear.
D．He does not think the causes of the sun spots will be fully revealed by scientists in the near future.
A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining.
In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate the lead sources. The dominant lead ratio found in Greenland snow matched that found ingasoline from the United States.
In a study published in the journal Ambio, scientists found that levels in soil in the Northeastern United States had decreased markedly since the introduction of unleaded gasoline.
Many scientists had believed that the lead would stay in soil and snow for a longer period.
The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected.
Scientists say both studies demonstrate that certain parts of the ecosystem respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute.
The study published in the journal Nature indicates that
A．the Clean Air Act has not produced the desired results.
B．lead deposits in arctic snow on the increase.
C．lead will stay in soil and snow longer than expected.
D．the U.S. is the major source of lead pollution in arctic snow.
