After being warned by his mother to swear off that demon knucklecracking, young Donald Unger tested the accuracy of this hypothesis on himself.
自从小时候受到母亲警告说不可以敲打指关节后，小唐就开始在自己的身上测试这种推断的准确性。
2
The US researchers behind that study concluded: 'The chief morbid consequence of knucklecracking would appear to be its annoying effect on the observer. '
这项研究的美国研究员总结道：“掰指关节的主要不良后果在于，关节的响声会让周围的人感到不舒服。”
3
The medicine prize went to a physician who, for fifty years, cracked the knuckles on only his left hand to test his mother's contention that knuckle-cracking causes arthritis.