问题
选择题
If we throw away too much waste and can’t keep good ecosystem,we _________ our future.
A．must have destroyed
B．could be destroying
C．may be destroying
D．must destroy
答案
C
must have destroyed表示对过去确有把握的推测。could be destroying表推测时常用于否定句和疑问句。may be destroying表示可能性,可能我们正在毁灭我们的未来。must destroy一定是,表示确有把握。从题意来看本题的最佳选项是C。