_______ for your laziness，you could have finished the assignment by now.
A、HaditnotbeenA
句意：要不是你懒惰，到现在你就能完成任务了。本题是一个省略if的虚拟条件句，主句用couldhavedone表示与过去事实相反，条件从句应用haddone形式，had要提前构成倒装。
Heblamedhispoorperformance_____jetlag.
Thenewdiscovery_______beofgreatservicetomankind.
If the operation ________ carefully prepared, it would not have been successful.
Thecentraltheatrehasaseating________ofmorethan3,000people.
Itisnousearguing_______theplanbecauseithasbeenrejected.
