我国提倡通过什么途径获得供体移植器官
A．自愿捐献
B．互换器官
C．器官买卖
D．强行摘取
E．强制捐献
参考答案：A
膳食纤维素的营养作用不包括
A．供给机体热能B．降低血胆固醇C．刺激肠蠕动D．预防大肠病、直肠癌E．增加粪便体积
A yellow signal floating in the air from a small parachute，about 300 feet above the water，would indicate that a submarine（）.
A.has fired a torpedo during a drill
B.is about to rise to periscope depth
C.is on the bottom in distress
D.is disabled and unable to surface
