If for any reason this does not happen, the ancestral feature may not disappear, leading to an atavism.

如果因为任何原因，这些事情没有发生，祖先的种种特性也许就不会消失，从而导致返祖现象。

youdao

These things happen for a good reason; they have social roots.

事出有因， 各有社会基础。

《新英汉大辞典》

But I am one of those people who believe things usually happen for a reason, even if it is a bad one.

相反，我是我属于这样一类人，即认为事情的发生时有原因的，即使是坏的。

youdao

The film is about all the bad things that happen to a common man for no apparent reason.

VOA: special.2010.03.01

That's why your operating systems and your personal computers often crash for no apparent reason. Just because two things happen to, once in a while, occur at the same time.

这就是为什么你的电脑或者操作系统,经常会毫无预兆的崩溃了,这是因为两件事情正好同时发生了，通常还有人工输入。

麻省理工公开课 - 计算机科学及编程导论课程节选

So let's imagine we're playing the game again, once again you're going to the movies, once again the first one didn't happen so you didn't for some reason it was cancelled that night because someone had a bad cold or something.

我们再来进行一次这个博弈,假设你们又要一起去看电影,由于种种原因,第一天晚上你们都没有看成,假装因为有一个人感冒了

耶鲁公开课 - 博弈论课程节选

So far I do not see any reason for this to happen.

FORBES: China's Crisis of Confidence

Of course, this book is geared towards women, as being bold for one reason or another, seems to happen less immediately for them.

FORBES: Lessons From Facebook's Sheryl Sandberg On How To Succeed In Business By Really Trying

There was no reason for the scheme not to happen because of the UK initiative, he added.

BBC: Home scheme axing dismays building firm Redrow