称为隐性肺动脉高压时,运动时的肺动脉平均压(PAPm)应大于()
A.20mmHg
B.15mmHg
C.30mmHg
D.35mmHg
E.25mmHg
参考答案:C
John didn’t go to bed ______he finished his homework.
A.until B.after C.while
GMSK调制是一种特殊的()
A、ASK调制
B、FSK调制
C、PSK调制
D、QPSK调制