a fragrant herb and a stinking weed put together—the good is often coverd up by the evil
? ～，十年尚猶有臭。(《左傳·僖四年》)There is a fragrant herb,and a noisome one; And ten years hence the noisomeness will continue.
一薰一蕕yi xun yi you
when a fragrant herb is placed besides a blade of stinking grass,you smell nothing but the latter
一薰一蕕yī xūn yī yóu
薰：香草；蕕：臭草。指把香草和臭草放在一起，香氣被臭氣掩蓋。比喻善惡不同類，善常被惡所掩蓋。good and bad can’t be classed together, the good is often covered up by the evil