I last saw him when I was a student.
I haven't seen him since I was a student.

A child was swimming across the Saigon River.
I saw a child swimming across the Saigon River.

The workers working in American factories learned English in 6 months.
It took the workers working in American factories 6 months to learn English.

I'm sorry I missed your birthday yesterday.
I wish I hadn't missed your birthday yesterday.

They arrived late because the traffic was terrible.
Because of the terrible traffic, they arrived late.

The students continued to talk about the party.
The students kept talking about the party.

I can't swim as well as Tom.
Tom can swim better than I can.

The old man is expecting with pleasure the visit of his grandchildren.
The old man is looking forward to the visit of his grandchildren.

It is a six-hour drive from London to Edinburgh.
It takes six hours to drive from London to Edinburgh.