风险矩阵中，严重程度的增加是下列哪项？（）
A、0–4
B、A–F
C、A–E
D、0–5
参考答案：D
列举两个实验：说明声音能传递信息或能量：______．
In the dark street, there wasn’t a single person _________ she could turn for help.
A．that
B．who
C．from whom
D．to whom
