问题
选择题
_________ is a growing world problem, and nowadays the United Nations and its member countries _________hard to deal with it．
A．Desertification; are working
B．Desertified ; worked
C．Desert; work
D．Desertification; have worked
答案
答案：A
第一空填：Desertification“沙漠化”，第二空考时态：句意是：沙漠化是日益严重的世界问题，现在联合国和成员国正努力对付它。用现在进行时，选A。