It was a very tricky operation to get the barrels safely down on to the road, up onto and across the pavement to the lift.

A pretty tricky operation for a species still mired in linear time, don't you think?

It cost a hell of a lot of money to do so; a very tricky operation.

I thought it an odd choice for what might prove to be a tricky operation.

It would be an intricate, tricky, and risky operation.

Locking onto a moving object that's any smaller than a planet, is an awfully tricky operation.

The other tricky operation, opening up Japan's rice market, will also please the Americans.

Not that Holly hadn't performed some tricky operations before.

"It's a tricky operation," said Richard, the 39-year-old special agent who heads the group.

Six people were rescued in a tricky operation in heavy seas.