would have是過(guò)去將來(lái)完成時(shí)。
例句：
He would have done better to play a spade now.
他要是現(xiàn)在出一張黑桃牌就更好了。
She would have scorned to stoop to such tactics.
她就不會(huì)下作到使用那樣的伎倆。