良渚文化

软件维护活动包括以下几类：改正性维护、适应性维护、 【3】 维护和预防性维护。

She         to catch the early train,but she didn’t get up in time. [ ]

A.intended

B.was intended

C.had intended

D.was intending

If we had taken such effective measures much earlier, the fiver ____ so seriously now.

A．is not polluted

B．would not be polluted

C．had not been polluted

D．would not have been polluted

网球单打场地是长23.77米，宽10.97米的长方形。

简述企业分立的动机。