Directions: Complete the following passage by using the words in the box. Each w

Directions: Complete the followingpassage by using the wordsin the box. Each word can only be used once. Note that there is one word morethan you need.

Forests in the northern halfof the globe could be growing faster now than they were 200 years ago as aresult 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 andhigher concentrations (浓度) of carbon dioxide in the ___1.___.

Geoffrey Parker, a scientistat 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 longergrowing seasons documented in the region. The growth may also be influenced bythe significant ___3.___ in atmosphericCO₂, he said.

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

Dr. Parker and hiscolleagues have ___5.___ out a detailedrecord of the trees on a(n) ___6.___basis since 1987. They calculated that due to the global warming the forest isproducing   ___7.___tons of wood each year.

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

试题答案

【答案】

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.