抛物线y2=﹣4x的焦点坐标是

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抛物线y²=﹣4x的焦点坐标是（　　）

A：（﹣2，0）

B：（﹣1，0）

C：（0，﹣1）

D：（0，﹣2）

上一题下一题 0.0难度选择题更新时间:2019-03-14 10:09:04

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There are too many cities around the world. And each city needs water in many ways. Water on Earth falls mainly as rain. So the rainfall (降雨量) is important to each part of the world. And it is different from one city to another. The following chart shows the average (平均的) rain fall in four different cities in July and January.

City	Guangzhou	London	Washington	Paris
Country	China	Britain	America	France
Rainfall in July	227.6mm	45.0mm	96.5mm	53.6mm
Rainfall in January	43.2mm	78.0mm	69.1mm	54.3mm

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