凡物价上涨就意味着通货膨胀,凡物价下跌就意味着通货紧缩。()
参考答案:错
正五边形绕着它的中心至少旋转 度后能与自身重合.
We must do everything we can _______ waste water from running into rivers. [ ]
A. keep
B. kept
C. to keep
D. keeping