以下哪个核反应堆不需要慢化剂（）？
A.压水堆
B.沸水堆
C.重水堆
D.快中子增殖堆
参考答案：D
— Where did you get to know her?
— It was on the farm _______ we worked.
A．that
B．there
C．where
D．which
工伤保险制度的特征。
