Had I known about this puter program, a huge amount of time and energy .
A. would have been saved
B. had been saved
C. will be saved
D. was saved
网友回答
(答案→)A. would have been saved
B. had been saved
C. will be saved
D. was saved
解析：句意：如果我了解电脑的话，大量时间和精力都会省下来了。如果省略if，那么把had,should,were提前，由从句的谓语动词可以看出这是对过去的虚拟，所以主句用would have done，故选A。