双曲线$\frac{x^2}{4}-y^2=1$的渐近线方程为（　　）

学习了隋唐史后，几位同学做主题演讲，最能准确概括这段历史基本特征的是（    ）

函数y=x²-2x+3的图象的顶点坐标是(      )

太阳、月亮、烛焰、镜子，属于光源的是____、____ 。

根据短文内容完成下列任务。

Cindy is my friend. She likes sports very much. She runs (跑步) every morning. Cindy is healthy and she eats well.

For breakfast, she likes eggs, bananas and milk. For lunch, she has chicken, tomatoes and vegetables. She likes fish, salad and carrots for dinner. She eats oranges, pears and apples, too. 水果和蔬菜是健康食品。She doesn't like ice-cream. And she doesn't eat hamburgers or French fries (薯条). They are not healthy food.