One of them hasnt prepared lessons very well.A. one’sB. hisC. theirD. our

问题补充：

One of them hasn prepared lessons very well.

A. one’s

B. his

C. their

D. our

答案：

A. one’s

(答案→)B. his

C. their

D. our

解析：不定代词one用作 “某一”解时，即其后有of+复数名词作定语，其所有格为his，不能用one来代表不可数名词。