放射治疗常用的放射源中,不包括以下哪一项()
A.钴60
B.磷32
C.碘131
D.中子
E.铀235
参考答案:E
Our school was going to send a teacher to Xinjiang . I was the first person _______ to go.
A.volunteer
B.to volunteer
C.volunteered
D.volunteering
剩余电流动作保护器标有“电源侧”和“负荷侧”时,不能反接。