let alone片语

更不用说、更别提、何况多用于否定句

He can't even boil an egg, let alone cook dinner.

他连水煮蛋都不会，更不用说做晚饭了。

别打扰、不去管可拆开

Let him alone for now; he needs time to think.

现在先别打扰他，他需要时间思考。