法洛四联症姑息性手术的主要目的是（）
A.降低右室负荷
B.减少心内分流
C.增加肺循环血量
D.改善体循环
E.改善心功能
参考答案：C
It's more than 8 years since I a teacher. [ ]
A. become
B. have become
C. became
D. becomes
要在当前状态页看故障的工程数据需输入（）。
A.100
B.200
C.300
D.400
