动脉导管未闭有显著肺动脉高压时可出现
A．头面部青紫
B．上半身青紫
C．全身青紫
D．末梢青紫
E．下半身青紫
参考答案：E
Would you please ___ the paper for me and see if there are any obvious mistakes?
A．look around
B．look into
C．look up
D．look through
管道材料的耗损通常是由于（）和（）等固体物在蒸汽或水的涡流作用下造成的（）。
