解方程：$\frac{2x}{2x-1}$+$\frac{x}{x-2}$=2；  

山脉往往成为我国省级行政单位的天然界线，如图所示的界线是（　　）

AMary: Hello, Gina. Do you want to have evening classes? On Monday evenings, there is a guitar (吉他) class.

Gina: I'm busy on Mondays. What about Tuesdays?

Mary: There's a class to teach you how to make bread. The teacher is Mr. Smith.

Gina: The class is useful. And Mr. Smith's bread is great. And Wednesdays?

Mary: That class is about clothes. You can learn how to make clothes.

Gina: It's fun. What class do you want to take?

Mary: Well, on Thursdays, there's one interesting class. I can learn how to make model planes.

Gina Oh, that's great. But I'm busy those days.

Mary: There is another (另一) interesting class on Friday evenings. You can learn about the stars.

Gina: It's boring. Is there a class on Saturdays?

Mary: Yes, you can learn how to take pictures.

Gina: Great! I like this class. I'll take it.

根据材料内容选择最佳答案。

利用两块长方体测量一张桌子的高度，首先按图①方式放置，再交换木块的位置，按图②方式放置，测量的数据如图，则桌子的高度是（      ）

在动员社会力量参与公共文化建设方面，烟台市工作起步早、措施好、成效显著。如果由你来主持一个关于政府向社会力量购买服务的讲座，你认为最适合的标题是（    ）