胸腔闭式引流管应插入液面下
A．1～2cm
B．3～4cm
C．5～6cm
D．7～8cm
E．10cm以上
参考答案：B
--He has practiced many times before the driving test.
--There ________ not be any difficulty in passing it.
A．must
B．should
C．shall
D．need
小儿腹进一步检查
