结构上并没有区别，选择would 或 could 要根据语境。例如：If he had waited one more minute, I would (could) have gone with him.他只要再多等一分钟，我就会（能）和他一道走啦....两者皆可，但语意有点儿出入。If he weren't so upset, I would have brought him along. 要不是他这么生气，我是会带他一块儿来的。... would 比 could 要更强调是“我的”选择Had I had enough money, I could have bought it without your help....
