woman runs away from a giant mummy during a Halloween promotion at a shopping mall in Hong Kong. AFP
The woman’s facial expressions can be interpreted in two ways:
grimace: 做出痛苦，厌恶的怪相、鬼脸
Perhaps she is pretending to be in pain. She grimaces as she is about to be “caught” by the person dressed in the mummy suit.
When the child touched the stove, he grimaced in pain.
那个孩子手碰到了火炉，作出一副痛苦的样子。
When she got up off the ground, she had a grimace on her face.
她摔倒了，从地上站起来，装出满脸痛苦的样子。
guffaw: 哄笑，狂笑
Some people might think that the woman is laughing. Perhaps the camera caught her in the middle of a loud guffaw.
During the professor’s lecture, a student let out a guffaw.
老师还在上课，一个学生忽然大笑起来。
howl: 狂笑，大笑
It’s a synonym with guffaw.
The movie had us howling.
这部电影让人捧腹大笑。