例如：下面這句話(huà)為什么用with不用for:The reason why she had not stopped at the red light was most probably that her eyes had become weak (with)old age.分析：with是介詞；而for表示“原因”時(shí),通常用作連詞...介詞with和for的區(qū)別1：
with一般有“和”的意思，如with sb.，但接sth.的時(shí)候意思應(yīng)該看語(yǔ)境；
for一般有“為”的意思，可以表示目的，如為某人、為了什么事，這時(shí)候可以用for。

介詞with和for的區(qū)別2：
For(介詞)：關(guān)于, 對(duì)于...來(lái)說(shuō), 考慮到...的事實(shí)
-- The weather is quite warm for November.
-- For him, this will be an entirely new hobby.
With(介詞)：在某一方面 (多用于二者的比較)
-- With some people, pleasure is more important than work.
-- Some people may accept that excuse, but it won‘t work with me.


望采納~~~
O(∩_∩)O謝謝