—What a mistake!
—Yes. I he do it in another way, but without success.
A. was suggesting
B. have suggested
C. would suggest
D. had suggested
网友回答
A. was suggesting
B. have suggested
C. would suggest
(答案→)D. had suggested
解析：句意：--多么严重的错误啊！--是的，我建议他用另外一种方法来做，但是没有成功。从What a mistake!可知错误已经造成，而建议他用另外一种方法做是在犯错之前，所以是过去的过去的动作，用过去完成时，所以选D。