更换车辆的制动液时，必须将车辆的（）清洗干净。
参考答案：制动系统
The young man came _______ to the airport hurriedly only_______his girl friend had already gone.
A．driving; to find
B．to drive; to find
C．and drove; found
D．driving; finding
下列哪种骨折为不稳定性骨折（）。
A、横断
B、锯齿形
C、粉碎性
