尾气膨胀机的转子由（）组成。
A.主轴
B.各级动叶
C.隔叶块
D.叶片锁紧装置
参考答案：A, B, C, D
What a nice day! You are not busy today. ______ go to the park with Sam?
A．What about
B．Why don’t
C．Let’s
D．Why not
下列哪项反射活动中存在着正反馈
A．腱反射B．排尿反射C．减压反射D．肺牵张反射E．对侧伸肌反射
