已知函数的定义域是R,则实数a的取值范围是().
A.
B.-12<a≤0
C.-12<a<0
D.
参考答案:B
解析:
由a=0或可得-12<a≤0.故选B
In the traffic accident, an _______ girl was badly hurt this morning.
A.eight-years-old
B.eight year old
C.eight-year-old
D.eight-years old
某水库库岸陡直,组成库岸的土层为弱透水的粉土,隔水层连续,近于水平,隔水层顶面高程为105m。蓄水前河水位为l30m,水库设计正常蓄水位为180m。距水库岸边600m的一片农田,水库蓄水前的地下水位为160m,不考虑地表人渗影响,水库蓄水后该处的地下水位高程约为()m。
A.180
B.185
C.190
D.195