Our capital, Beijing, ______ on improving the city’s environment in the past thr

题干

Our capital, Beijing, ______ on improving the city’s environment in the past three years through various measures.

A．has been working	B．were working
C．worked	D．had worked

上一题下一题 0.65难度单项选择更新时间:2019-08-05 06:01:42

小学学科试题库

初中学科试题库

高中学科试题库