I bought a train ticket.

He finished the job in just one hour.

His salary alone was not enough to cover living expenses.

I bought a train ticket.

I ate only one apple.

Due to yesterday's heavy rain, earth and sand flowed down from the mountain.

He ate three apples.

There is reason in what he is saying.

No wonder he is so tired, he has been working all day.

No wonder, I understood why he is so tired.