爆炸按其性质可分为( )。
A．核爆炸
B．物理爆炸
C．化学爆炸
D．自然爆炸
E．生物爆炸
参考答案：B,C
The man， so badly，almost lost his memory and was even driven mad．
A．to have been disturbed
B．having been disturbed
C．to be disturbed
D．being disturbed
下列哪项不是脐带过短的表现
A．脐带长度短于30cm
B．脐带脱垂
C．引起胎儿窘迫
D．阻碍儿头下降
E．造成胎盘早剥
