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. 如果我钱够的话,我完全可以自己买的....这样的语气存有赌气的可能.