The thick smoke covered the whole city.It looked as if a gre
The thick smoke covered the whole city.It looked as if a great black blanket ______over it.
A.was thrown B.is thrown C.has been thrown D.had been thrown
答案是选D,可我觉得应该选A,不是主句加as if 再加主语+过去时表示与主句动作同时发生么?