The research shows that during the 20th Century rainfall in the Sahel dropped between 20 and 30 percent.
研究显示在20世纪期间，撒海尔的降雨下降了20%到30%。
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Possible causes of the vegetation shift include declining rainfall, growing human population and decreasing soil fertility
可能造成植被转移的原因包括降雨量的下降、人口的增长以及土壤肥力的减弱。
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作者: sama 时间: 2011-12-22 16:07
One ？ is died in the last half beteen 20 century, and second one in five tree speech is disappear locally. and then third, together these changed shifted vegetation though ? world area of marine ?作者: 雨落风残 时间: 2011-12-24 20:26
One in six trees died in the last half of the 20th century and second one in five tree species disappeared locally and then third, together, these changes shifted vegetation ___ southwards towards areas of more rainfall.作者: 我是君君 时间: 2012-2-9 12:12
