问题补充:
Enough to stop the forest since the 1980’s.
A. has been done;be cut down
B. has done;cutting down
C. has been done;being cut down
D. had done;from being cut down
答案:
A. has been done;be cut down
B. has done;cutting down
(答案→)C. has been done;being cut down
D. had done;from being cut down
解析:考查时态和非谓语动词。since the 1980’s是现在完成时的标志,根据语境应该用被动形式;stop sth.from being done是“阻止……被做……”。