Explain why you didn't telephone.

解释一下你为什么不打电话。

《柯林斯英汉双解大词典》

I really don't see why I should have to explain myself to you.

我真不明白我为什么非要向你解释我的行为不可。

《牛津词典》

Let me explain why.

让我来解释为什么。

《柯林斯英汉双解大词典》

She says there is no information to explain in detail why tobacco smoke causes behavioral problems in children with asthma.

VOA: special.2009.01.13

It has traditional stories and legends, some quite fanciful, Whose goal it is to explain how and why something is what it is.

它讲述了一些传统故事，有一些还极具想象力，它们试图解释事物的形成方式及成因。

耶鲁公开课 - 旧约导论课程节选

Can you explain to us about stem cell research and why it's so controversial?

你能跟我们解释一下干细胞研究，
以及为什么这项研究会受到这么多的争议吗？

干细胞和伦理 - SpeakingMax英语口语达人

If you were opposed to this legislation, you should obviously explain why, and you should explain why you are for something that 90 -- you are against something that 90 percent of the people are for, that vast majorities of the people in your state support.

WHITEHOUSE: Press Briefing

And inasmuch as NBC seems intent on ruining the Olympics regardless of how much we and others scream, why not explain to America why it is choosing to do this?

FORBES: Pressure Builds On NBC To Explain Why It's Ruining The Olympics

These political and systemic differences may explain why one Blairite flunkey was heard to explain recently that in Europe there will be a set of third ways, not a single third way.

ECONOMIST: Anglo-German relations