The old man wondered why life had passed him by.

Frankly speaking, it's difficult to understand why you want to go.

My alarm clock didn't work. That's why I was late.

Why was the Japan Defense Agency upgraded to the Japanese Ministry of Defense?

Then, if so, why were the like of Kyouou let upon the throne?

I wonder why she didn't tell him about it.

He completely failed to understand why she got angry.

I didn't know the reason why she began to cry.

Do you know the reason why she is so angry?

I don't know the reason why she isn't coming.