卫星移动通信是指利用卫星转接实现（）或移动用户与固定用户间的相互通信。
参考答案：移动用户间
The professor could tell by the ________ look in Maria's eyes that she didn't understand a single
word of his lecture. [ ]
A. cold
B. blank
C. innocent
D. fresh
细支气管不完全阻塞所致的阻塞性通气障碍可造成（）。
A．肺不张
B．肺纤维化
C．支气管扩张
D．气胸
E．肺气肿
