I don't say why as you can guess.

我不说你们也知道原因。

youdao

Why don't they stop pussyfooting around and say what they really mean?

为什么他们不能不再小心翼翼，而是说出自己的心里话？

《柯林斯英汉双解大词典》

You might say, "Well, gee, why don't we just power our cars with hydrogen placed on an internal combustion chamber."

你可能会说：“好吧，哎呀，为什么我们不把氢气放在汽车内部的燃烧室，来驱动我们的汽车呢。”

youdao

Well,I got them saddles built, and then somebody would say 'Hey,why don't you build me a saddle?'" That was how Nancy Martiny got into the saddle making business twenty years ago.

VOA: special.2011.01.31

So, you might say, well, gee, why don't we just power our cars with hydrogen, use an internal combustion chamber.

你可能会说，好吧，哎呀，为什么我们不把氢气,放在汽车内部的燃烧室，来给我们的汽车提供动力呢。

麻省理工公开课 - 固态化学导论课程节选

But for me, I like to look at something and just say, "I like this. I don't really know why though."

但对我来说，我喜欢看着某个东西，然后说，“我喜欢这个。但我也不知道为什么。”

关于现代美术 - SpeakingMax英语口语达人

U.S. officials say they don't know why the text messages weren't provided earlier.

WSJ: U.S.: Russia Withheld Intel on Boston Bomb Suspect

You say you don't know why we are fighting -- what we are trying to accomplish -- and even whether we are "at war" at all.

CNN: What Obama should say about Libya

That is to say, we don't get why this really needs MotionPlus, at least for relatively casual players like us.

ENGADGET: Wii MotionPlus review: it works, but so far the games aren't worth the fuss