口腔主要致龋菌不包括（）。
A．口腔内氏放线菌
B．口腔螺旋杆菌
C．口腔变形链球菌
D．口腔粘性放线菌
E．口腔乳酸杆菌
参考答案：B
The company has a free long-distance telephone number _____ customers may call with any question
they have about its products.
[ ]
A. so that
B. although
C. even if
D. as though
不属于冷却塔冬季防冻措施的有（）
A.减少进水
B.减小风机叶片安装角度
C.风机定时反转化冰
