光学内镜是
A．一类医疗器械 B．二类医疗器械 C．三类医疗器械 D．试产品 E．准产品
参考答案：B
Many experts hold the view ____teacher development is _____the key to better education lies.
A．which, where
B．which, in which
C．that, where
D．that, in which
遇有恶劣天气或能见度不良时，海事管理机构可（）高速客船停航。
A、要求
B、建议
C、强迫
