剂量评价中，当放射性工作人员的年受照剂量达到并超过（）时，除应记录个人监测结果外，还应估算人员主要受照器官或组织的当量剂量。
参考答案：20mSv
What is this talk mainly about
A．How historical events affected an art movement.
B．How artists can influence economic conditions.
C．Why a certain art movement failed to become popular.
D．How valuable paintings were lost during wartime.
内外服制
