be in black and white
以黑白方式表达或记录，即以书面或正式的方式表达
书面语·强调书面证据或明确条款
英文释义
to be clearly and definitively stated or documented
例句
Make sure the terms are in black and white before you sign the contract.
典故来源
源自印刷时代，文字以黑白墨水呈现，象征正式、明确且不可否认的记录。