正常飞行中放襟翼后飞机的升阻比（）.
A.增大
B.减小
C.无法确定
参考答案：B
Tony knows China very well because he ______ in China for twenty years.
A．works
B．was working
C．will work
D．has worked
信息在信息源和信宿之间传递过程理想模式（）
A.完全接收
B.消耗殆尽
C.有损耗
D.混有其他信息
