英文：speechless (adj.)
說明：「臉上三條線」就是「(啞口) 無言；傻眼」。
例句：
- Mrs. Huang was speechless when she saw several topless photos of her daughter online. (黃太太在網路看到她女兒的上空照時當場臉上三條線)
- I was really speechless about his rude behavior at the restaurant last night. (對於他昨晚在餐廳的粗魯行為，我真是臉上三條線)