国际上首次提出“安全文化”概念是在（）事件之后。
A、美国三里岛核事故
B、切尔诺贝利核事故
C、日本广岛核爆
D、美国“曼哈顿计划”
参考答案：B
He didn't tell his parents he was going home because he wanted to give them a . [ ]
A. joy
B. surprise
C. shock
D. happiness
导热系数
