铜带轧纹处破口或缺口的防止办法是调整轧纹轮之间的（）和平行度。
参考答案：距离
She has a gift for creating an atmosphere for her students ______ allows them to communicate freely with each other.
A．which
B．where
C．what
D．who
肺泡与肺毛细血管之间的气体交换称为（）
A.气体交换
B.肺通气
C.肺换气
D.内呼吸
E.外呼吸
