rob the cradle”字面意思为“抢劫摇篮”，实际含义为“老牛吃嫩草”。

【例句】
Don't rob the cradle, she is too young for you.
你不要老牛吃嫩草，她对你而言太年轻了。

His friends accused him of robbing the cradle when they saw how young his girlfriend was.
朋友们看到他带着一位过于年轻的女朋友，都指责他老牛吃嫩草。