He was working late at night.

The phone rang in the middle of the night.

He was working throughout the entire night.

He was able to recall the poem immediately.

I couldn't sleep because I could hear the howling of a dog in the middle of the night.

The dog howled in the middle of the night, and I couldn't sleep.

It's difficult to remember his name.

It's difficult to remember new words.

His threat is just a bluff.

My dog is very smart.