发动机因（）油底壳机油平面会升高。
A.发动机温度过高
B.活塞与气缸套间隙大
C.气缸垫损坏
D.发动机机油过稀
参考答案：C
—Are there any balls under the chair? —________.
A．Yes, there is
B．Yes, they are
C．Yes, there are
D．No, there are
辨析：我国生育社会保险的缴费基数以城镇企业女性职工的工资总额为基数。
