为了正确处理紧急情况，压力容器的操作人员应该了解操作容器的（）。
A.危险点
B.紧急情况处理预案
C.事故报告制度
参考答案：A, B, C
All that he had learned only made him feel how little he knew in comparison with ______ remained to be known.
A．what was
B．what
C．which was
D．that
〈IMG〉标记中图片地址的属性为（）
A.link
B.text
C.vink
D.srC
