The stock exchange has undergone rapid expansion.

They were promised food in exchange for oil.

Instead this will be an exchange of information.

Secondly, we must promote an exchange of ideas.

Such fluctuations are inevitable in a floating exchange rate system.

Finally, it must not be a case of the last person off the island turning the lights off.

The neighbourhood was tipped off in time and the whole plan was called off.

Free trade is not the end; free trade is a means to an end.

I have written off that problem.

We must begin by writing off debts.