don't play dumb 别装傻；别装无辜；别装作什么都不知道

【例句】
Don'tplay dumb,I know you ate the last piece of cake.
别装傻了，我知道你吃了最后一块蛋糕。

Don't play dumb with me-I know you took the money.
别跟我装傻，我知道你拿了钱。