单选题 A person who is constantly worried about the loss of ______ job is not likely to do very good work.

【正确答案】 A

【答案解析】a person其后对应的物主代词为his。一般one对应的物主代词为one's(英国英语)或his(美国英语)，故C项错误。their前的名词或代词应是复数名词或they，故B项错误。