A: Have you heard? John was diagnosed with cancer.

    B: Yeah. It’s so unexpected. He seemed so healthy. I just pray nothing like that ever happens to my family, knock on wood.

    Note: This phrase is used by people who rap their knuckles on a piece of wood hoping to stave off bad luck. In the United Kingdom, the phrase “touch wood” is used — often jokingly by tapping one’s head. The phrases are sometimes spoken when a person is already experiencing some good fortune and hope that it will continue. The derivation may be the association that wood and trees are with good spirits in mythology, or with the Christian cross. It used to be considered good luck to tap trees to let the wood spirits within know you were there. Traditions of this sort still persist in Ireland.