硬膜外麻醉期间最严重的并发症（）
A.全脊麻
B.硬膜外血肿
C.硬膜外脓肿
D.神经损伤
E.脊髓前角动脉综合征
参考答案：A
阅读短文，给下列句子排序。
I went to a park by bike. I flew kites. It was a windy day. Suddenly my kite flew into the lake.
A dog saw the kite. He jumped into the lake and swam to it. Five minutes later, he returned the kite to me.
I was very grateful to him.
( ) I went to a park.
( ) He returned the kite to me.
( ) He swam to the kite.
( ) The dog jumped into the lake.
( ) The kite flew into the lake.
绘图题：画出直流电源的图形符号。
