问题
选择题
A qualified doctor has to constantly update his knowledge in order to maintain his professional _____.
A．conscience
B．competence
C．conservation
D．convenience
答案
答案：B
题目分析：A. conscience意识，B. competence能力，C. conservation保护，D. convenience便利，句意：一个合格的医生不得不不断的更新他的知识为了保持他的专业技能。选B。