胆道手术前后患者每日脂肪补充不能超过（）。
A.40g
B.10g
C.30g
D.20g
E.50g
参考答案：C
.
Hundreds of houses fell down in the earthquake It seemed________that everything
happened．
A．all of a sudden
B．in a hurry
C．to our surprise
D．in a while
什么是典型故障树？
