He was waiting a chance to prove of himself but things go co

原句：He was waiting a chance to prove of himself but things go contrary to one's wishes.
中文：他正在等待一个机会去证明他自己但那些东西却不符合他的愿望（事与愿违）.
其实只有两处错误.一个是时态不一致,一个是宾格不正确.
但时态可以有两种改法,一是改成过去式,另一个是改成现在时.
1、改成现在时的（也是你问题中建议的）：
He is waiting a chance to prove of himeself but things go contrary to his wishes.
2、改成过去式的：
He was waiting a chance to prove of hime self but things went contrary to his wishes.
为什么习惯性地改成现在时呢?因为通常非故事阅读类的题目中的句子都是单一的,不是过去的,所以通常改成现在时.

was改为has应该是这样

如果要把he后的谓语动词改为第三人称单数，那么就改成
He was waiting a chance to prove of himself but he failed to get one
他期待一个机会来证明自己但是他没有等到(这个机会)

He was waiting a chance to prove of himself but things go contrary to one's wishes。
其实是时态不一致。
前半句你用了过去时，后半句是一般现在时。
因此建议你修改成：
He waits a chance to prove of himself but things to contrary to his wish.

前半句已经说了是he为主语，译为：他一直在等待一个机会来证明自己，可是事与愿违。事与谁的愿违呢？当然是his，所以不能用one's.
另外go要改成和was一样的时态——过去时went
改为：He was waiting a chance to prove of himself but things went contrary to his wishes....

这句话为啥看起来漏洞如筛子一样……难道我学的语法都过时了？
waiting a chance难道不要加个for吗？
prove of himself其实不要of就行了吧？
go应该是went吧？
one's应该是his吧？