动脉导管未闭患者在哪种情况下可能出现差异性发绀()
A.患者为婴儿
B.重度肺动脉高压双向分流
C.动脉导管瘤
D.导管为漏斗形
E.伴发细菌性心内膜炎
参考答案:B
The conference was attended by more than 11,000 people, _____ it the largest UN climate change gathering ever held.
A.making
B.to make
C.made
D.to be making
对220kV及以上电网电压进行控制和调整时,其控制原则为()。
A.逆调压
B.顺调压
C.恒调压
D.自动调压