a scowl on his face的用法和样例：
- He wore a permanent scowl on his face.
- The angry scowl on his face, the veins in his feet, the wrinkles on the skin of his elbows, the glare of his bloodshot eyes.
- The scowl on his face is not from disgust or anger;rather, it results from how these big cats scrunch up their nose to keep water out.
- He stumbled over a stump and fell flat on his face.
- He has a very fierce look on his face.