She accidentally blew someone's cover when she mentioned their secret mission.

He is blowing someone's cover by revealing their secret identity.

I always make sure to cover all of my bases before making a decision.

Don't judge a book by its cover.

Never judge a book by its cover.

You can't judge a book by its cover.

You can't tell a book by its cover.

The coversin of an angle is equal to the ratio of the length of the side opposite the angle to the length of the hypotenuse.

The coversine of an angle can be calculated using trigonometric functions.

The coversed sine of an angle is equal to the reciprocal of the cosecant of the angle.