van der Waals' force

http://210.240.77.137/nano/nano2.htm

The man whom you saw just now is a TV star.

The man with whom she had an argument yesterday is one of her relatives.

Mr Lee, about whom she has just talked, is her former employee.

You'd better think about it.

I'd rather wait here a little longer.

Sam is a hard worker.

Sam works very hard.

Sam hardly ever fails in the tests.

I have just met him.

I met him just now.