用一句话概括下面这条新闻的要点（不超过25个字）。

    据英国广播公司报道，德国汉堡大学的天文学家在银河系中发现了一颗已有140亿年历史的恒星。它的形成能够追溯到宇宙形成的初期。这颗恒星被编为HE0107—5240。其罕见之处在于：与其它历史稍短的恒星不同，它完全是由宇宙大爆炸时产生的几种简单元素组成的，是迄今为止发现的第一颗不含金属元素的恒星。

新能源汽车环保节能，越来越受到消费者的喜爱．各种品牌相继投放市场．一汽贸公司经销某品牌新能源汽车．去年销售总额为5000万元，今年1～5月份，每辆车的销售价格比去年降低1万元．销售数量与去年一整年的相同．销售总额比去年一整年的少20%，今年1﹣5月份每辆车的销售价格是多少万元？设今年1﹣5月份每辆车的销售价格为x万元．根据题意，列方程正确的是（   ）

中东的大多数居民信仰

在直角坐标系xOy中，曲线M的参数方程为$\left\{\begin{array}{c}x=\sin \theta +\cos \theta \\ y=\sin 2\theta \end{array}\right.$（θ为参数），若以直角坐标系的原点O为极点，x轴的正半轴为极轴建立极坐标系，曲线N的极坐标方程为ρsin（θ+$\frac{\mathrm{\pi }}{4}$）=$\frac{\sqrt{2}}{2}$t（其中t为常数）

（1）求曲线M和N的直角坐标方程；

（2）若曲线N与曲线M只有一个公共点，求t的取值范围．

阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处 填入一个适当的词或使用括号中词语的正确形式填空。

    Long long ago, there was a wild donkey and a tame (驯服的) donkey.

    The wild donkey was thin and small. He spent his life outdoors. ____ grass on the hill was his food. Sometimes, he had to walk miles to find water. At night there was ____ (dangerous) from wolves.

    The tame donkey was fat and strong. The owner gave him grass ____ he felt hungry. There ____ (be) always water for him to drink. At night he stayed in a stable (驴棚) ____ (safe).

    The wild donkey wanted to live like the tame donkey.

    One day, the wild donkey was looking for grass on the hill. He saw the tame donkey walking slowly along the road. The tame donkey was carrying a ____ (heavily) bag. The tame donkey felt tired and hungry. He wanted to stop ____ (eat) some grass by the road.____ his owner didn't agree. He began to beat the tame donkey ____ a stick.

    The wild donkey changed ____ mind. He didn't want to live like the tame donkey any longer.