Had it not been for the fact that about 30 pupils __________ in the state of Connecticut a fortnight ago, their parents ___________ in deep sorrow now.

A．had been killed, wouldn’t be

B．were killed, couldn’t be

C．would have been killed, mightn’t be

D．should be killed, wouldn’t be

下面叙述正确的是

A．算法的执行效率与数据的存储结构无关

B．算法的空间复杂度是指算法程序中指令(或语句)的条数

C．算法的有穷性是指算法必须能在执行有限个步骤之后终止

D．以上三种描述都不对