結(jié)構(gòu)上并沒(méi)有區(qū)別,選擇would 或 could 要根據(jù)語(yǔ)境.
例如：
If he had waited one more minute,I would (could) have gone with him.
他只要再多等一分鐘,我就會(huì)（能）和他一道走啦.兩者皆可,但語(yǔ)意有點(diǎn)兒出入.
If he weren't so upset,I would have brought him along.
要不是他這么生氣,我是會(huì)帶他一塊兒來(lái)的.would 比 could 要更強(qiáng)調(diào)是“我的”選擇
Had I had enough money,I could have bought it without your help.
如果我錢(qián)夠的話,我完全可以自己買(mǎi)的....這樣的語(yǔ)氣存有賭氣的可能.