Further delays would be a mistake.

That was a very bad mistake.

39818 That was a serious mistake.

You have made a mistake in this case.

A slapdash enlargement would obviously be a great mistake.

We should not err by doing nothing.

Far better to err on the side of caution.

To err is indeed human -- very human.

To err is human, but to persist in error is another matter.

If you do start to think about it, then you make a mistake.