We all have opinions, but none of us can be absolutely certain about the answer.

Most contestants abstain after the expert has been successfully called upon unless they are absolutely certain they have the correct answer.

The reason for that is they will not take action until they are absolutely certain they are on robust and strong ground.

Nobody is sorrier than I am that this thing has started, but having entered into it, we shall make absolutely certain that we win.

You have to be absolutely certain that not only the head of the organisation but the board of trustees are unimpeachable.