1. 这里应该理解为:到退休前的那一天,他将从教整40年。(on) the day before his retirement. 主句使用将来完成时。如果改用by从语法角度没错,但未必完全符合原意,因为by = on/before,不一定就是那天,也可能早一两天。请看例句:1. We will have been married a year on June 25th.(《朗文英语语法》例句) 2. On 14 October I will have worked here ten years.《剑桥词典》https://dictionary.cambridge.org/zhs/%E8%AF%8D%E5%85%B8/%E8%8B%B1%E8%AF%AD/future-perfect
2. 原文没有问题,当然你如果改用came away from his hands也对。也可以说came out of his hands.其实几个意思都差不多。你要不断熟悉英语不同形式的表达。请看外刊例句:
1. His wooden cup came away from his hands and landed at the feet of the Lord.
2. Just as the forked spear started to come away from his hands, she brought the baton around in a tight semicircle to crack on top of it.
3. Then the apparatus suddenly came out of his hands and he felt pain on the under side of the left forearm between the hand and elbow.