问题 填空题

向一个圆内随机投一点,则所投的点落在圆的内接正方形内的概率为______.

答案

由题意可得:此事件的概率符合几何概率模型.

设圆的半径为r,

因为正方形是圆的内接正方形,

所以正方形的边长为

2
r.

所以圆的面积为:πr2,正方形面积为:2r2

所以落在正方形内的概率为:

2r2
πr2
=
2
π

故答案为:

2
π

写作题

阅读下面的短文,然后按照要求写一篇150词左右的英语短文。

No doubt the planet is warming. Over the last century, the temperature has risen by around one degree Fahrenheit. It’s reported that the global temperatures will rise  by 3-10 degrees Fahrenheit—enough to have the polar caps almost melted. If the ice caps melt, buildings, homes and even lives will be under water.

While we know about global warming,  what can we do to save the planet? The answer is simpler than supposed. You don’t have to go miles away to protest, or spend much money. Here are several simple steps to begin with.

Firstly, plant a tree.Trees , when fully grown, will keep the plante cooler.

Secondly, reduce pollution. Sometimes as simple as walking instead of taking the car will reduce pollution. Besides stop pollution, you are giving yourself exercise. So whenever you get into your car, just ask yourself, “do I have to make this journey by vehicle?”

When you get a little cold in winter, put a jumper on and don’t adjust the heating. The extra heat produced by homes also affect the planet.

Finally, reduce, reuse and recycle. Only buy what you need and reuse whatever you can, like containers and paper, and recycle what you cannot reuse.

If everyone stuck to these rules, we would be doing a great thing by protecting the Earth. It is our next generation that will feel the effects.

[写作内容]

1. 以约30个词概括这段短文的内容 ;

2. 然后以约120个词就“阻止全球变暖从我做起”进行议论,内容包括:

(1)全球变暖危及人类生存;

(2)阻止全球变暖要从小事做起;

(3)你的做法。

[写作要求]

1. 在作文中可以使用自己亲身的经历或虚构的故事,也可以参照阅读材料的内容但不得直接引用原文中的句子;

2. 标题自定。

[评分标准]

概括准确,语言规范,内容合适,篇章连贯。

单项选择题