已知 $a\ge 0,b\ge 0$  ，且a+b=2 ，则(    )

阅读材料，回答下列问题

材料一“蓉欧快铁”货运直达列车于2013年4月26日开始运行。“快铁”线路西端的欧洲中部地区有世界著名的传统工业区，钢铁、汽车制造工业历史悠久；东端的成都平原地区有国家级高新技术产业开发区，电子工业、汽车工业发展较快，两端广阔的货物集散区域经济互补性强。

材料二“蓉欧快铁”运行线路图（图6），甲区域等高线地形图（图7）

钟面上是____∶____．再过____分钟是3时整．

补全对话

从方框中选择最佳选项完成对话。

a. How much is it, please?

b. Oh, yes. We have blue, yellow and white ones.

c. Which one would you like, please?

d. I'll take this one.

e. Can I help you?

A: ____

B: Yes, please. I want to buy a sweater.

A: ____What about this one?

B: I don't like black. Do you have any other colours?

A: Other colours? ____

B: Can I have a look at the yellow one?

A: Yes, please.

B: ____

A: Ninety yuan.

B: OK. ____Here's the money.

A: Thank you.