就譬如the lamb is ready to be eaten.比起the lamb is ready to eat.是否更好呢？
主语是“物”， be ready 后的不定式跟主语存在动宾关系时，用被动式或主动式均可以。主动时，可以看作在不定式之前省略了由 for 引出的逻辑主语。比如：
The apples are ripe and ready to eat. 苹果完全熟了，随时可以享用。
You need to boil the dumplings for 10 minutes, and then they will be ready to eat. 你得把饺子煮上十分钟才可以吃。
In a few days time the sprouts will be ready to eat. 再过几天球芽甘蓝就能吃了。
《柯林斯高阶英汉双解学习词典》
Soon the bananas would be ready to eat. 非常快香蕉就可以吃了。
以下是用被动式的句子：
I have wrapped up the parcels and theyre ready to be posted. 我把包裹都包好了，可以寄出去了。
The potatoes are ready to be dug up. 快要收成土豆了。
The steel is then ready to be cast into different shape and size. 这个时候的钢水可以被浇铸成各种大小不一样的形状。
