He blows someone's cover by accidentally mentioning the code name in public.

The agent realized that the leaked photograph had blown someone's cover, jeopardizing the entire mission.

It's wise to cover all of one's bases before launching the product.

When he arrived, I told myself 'don't judge a book by its cover,' and I was surprised to find out how thoughtful he was.

Meeting the shy artist reminded her that you should never judge a book by its cover.

People often assume he's unfriendly, but you can't judge a book by its cover; he actually organizes community events and helps his neighbors.

She reminded him that you can't tell a book by its cover when he dismissed the shy candidate.

As the rain intensified, thou coveredst the small chest with oilcloth to save the letters inside.