Question

Directions: Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.

A. additional   B. producing   C. regular     D. predicted   E. identified E atmosphere  G. matched     H. reducing   I. carried      J. increase

Forests in the northern half of the globe could be growing faster now than they were 200 years ago as a result of climate change, according to a study of trees in eastern America. The trees appear to have faster growth rates due to longer growing seasons and higher concentrations (浓度) of carbon dioxide in the ___1.___.

Geoffrey Parker, a scientist at the Smithsonian Environmental Research Centre in Edgewater. Maryland, said that the increase ha the rate of growth was unexpected and might be ___2.___ to the higher temperatures and longer growing seasons documented in the region. The growth may also be influenced by the significant ___3.___ in atmospheric CO₂, he said.

"We made a list of reasons these forests could be growing faster and then excluded half of them," Dr. Parker said. Their study suggests that northern forests may become increasingly important in ___4.___ the influence of man-made CO₂ on the climate.

Dr. Parker and his colleagues have ___5.___ out a detailed record of the trees on a(n) ___6.___ basis since 1987. They calculated that due to the global warming the forest is producing   ___7.___ tons of wood each year.

The scientists ___8.___ the land with trees at different stages of growth and found that both young and old trees were showing increased growth rate. More than 90 per cent of the tree groups had grown by between two and four times faster than the scientists had ___9.___ from estimates of the long-term rates of growth.

Answer

1.F. 此句意思是大气中二氧化碳的浓度加深。

2.G.

3.J. 大气中二氧化碳的增加用increase。

4.H. 根据常识，森林的增加有助于减少二氧化碳对天气的影响。

5.I. carry out 实行，实施。

6.C. on a regular basis: 定期的

7.A. 根据文章大意，可知此处应是产生额外的(additional)木材。

8.E.

9.D.