彼は何が起きてるのか、分かってなかったんだ。の英語

He didn't realize what was happening.

I didn't know what had happened.

he had no inkling what was about to happen

I don't know what has become of him.

Little did he know what was going on behind his back.

No one knows what became of him.

There is no way that he didn't know anything.

What with drink and (what with) fright, he did not know what was happening.

He hasn't realized what he's doing.

He was unaware of the situation.

I didn't know he was coming.

He seems to know nothing about the matter.

He cannot have done such a thing.

He could make nothing of it.

I did not notice his absence―I did not miss him―at the time.

I don't know for certain when he will come.

It seemed as if he knew nothing about that.

It is certain that he didn't know that.

He cannot have said so.

He never overlooks anything

Nothing ever escapes his notice.

There is no way that I didn't know that.

What he says makes no sense at all.

He cannot have done such a silly thing.

No one knows what has happened to him.

He didn't know that.

He must have known that.

I didn't know where he came from.

I don't know if he came or not.

He doesn't know that at all.