矿井必须有完整（）的通风系统。
A、联合
B、统一
C、独立
D、分立
参考答案：C
_______is known to all ,the Diaoyu Islands have been part of Chinese territory since ancient times.
A．It
B．That
C．This
D．As
教师应如何尊重家长及其育儿方式?
