Unit 1 Festivals around the world grammar课时作业

第一节 阅读理解

　　The amount of carbon taken in by growing plants increased from 1982 to 1999 as temperatures rose and the amount of carbon dioxide in the atmosphere increased. But a new study in Friday's edition of the journal Science found a drought－related decline in such plant growth from 2000 to 2009，even though temperatures continued to climb.

　　As drought caused by warming reduces the land's ability to take in carbon，the result could be more carbon dioxide left in the atmosphere，and thus more warming，Zhao Maosheng，from the University of Montana explained in a telephone interview.

　　"This is a pretty serious warning that warmer temperatures are not going to endlessly improve plant growth，"co-author Steven Running，also from the University of Moutaua，said in a statement. "We see this as a bit of a surprise，and potentially significant on a policy level because previous interpretations suggested global warming might actually help plant growth around the world，"he said.

　　Instead，he and Zhao found a small but measurable decline of about 1%，compared to a 6%increase in the past decade.

Their study，based on the data collected by NASA satellites，found that north areas continued to increase plant growth，thanks to warmer temperatures and a longer growing season.