通过实验我们得出了结论：水、食用油、洗洁精流的最快的是（    ）。

下列表格中各项都正确的一组是                                     

我国某地经济发达，其主要经济支柱有博彩、旅游、工业、建筑业等，环境幽雅，中年绿树繁花，素有“海上花园”之称，该地是（　　）

阅读理解
    Mr. Black is American, but he is in Canada now. He is a tall man with funny glasses. He works in a big city but lives in a town far away. He lives on the twentieth floor of a building. Every morning he gets up early. Then he gets into the lift and it takes him down to the first floor. He runs to the bus stop and catches the early bus. It usually takes him about two hours to get to the factory by bus. Then he gets off the bus and walks into the workshop(车间) quickly. He starts his work at eight in the morning.

双曲线的左焦点为F，点P为左支的下半支上任一点（非顶点），则直线PF的斜率的范围是（　）