在选择开关安装的高度时,选取的百分数据应为()
参考答案:第50百分位
平面汇交力系平衡的必要与充分条件是什么?
---________? ---It was sunny.
A.What’s the weather like?
B.What’s the weather?
C.How is the weather like?
D.How was the weather?