缘故

tā zhè shí hái méi yǒu lái bù zhī shì shén me yuán gù

他这时还没有来，不知是什么缘故。

I wonder why he hasn't come yet.

zhè shì qí zhōng yuán gù

这是其中缘故。

This is the reason why.

méi rén zhī dào tā zhè me zuò de yuán gù

没人知道他这么做的缘故。

No one could know why he did like that.

bù zhī shì hé yuán gù

不知是何缘故

not know why

chū yú wèi shēng de yuán gù

出于卫生的缘故

for health reasons

wèi le mǒu rén de yuán gù

为了某人的缘故

for the sake of someone

wǒ zhè me jiǎng shì yǒu yuán gù de

我这么讲是有缘故的。

I have reasons for it.

xià dà xuě de yuán gù kàn bù jiàn wū dǐng

下大雪的缘故，看不见屋顶。

The roof was not visible because of the heavy snow.