单项选择题

Most environmental problems exist because adequate measures for preventing them（）taken in the past.

A．was not
B．were not
C．were not being
D．had not been

<上一题 目录 下一题>
热门 试题

单项选择题
I know nothing about his journey（）he was likely to be away for three weeks.

A．if
B．unless
C．until
D．except that
单项选择题
May I stay with you and Jack（）going back to my parent's home this afternoon

A．because of
B．so as to
C．in spite of
D．instead of
相关试题