来自祁晓瑾的问题
Withinthelast3years,enough()(do)topreventtheriversfrombeingpolluted.此题答案为hasbeingdone,我不明白为什么要用hasbeingdone而不用hastobedone
Withinthelast3years,enough()(do)topreventtheriversfrombeingpolluted.
此题答案为hasbeingdone,我不明白为什么要用hasbeingdone而不用hastobedone
