设数列{xn}满足关系(n=0，1，2，…)．证明：无论x0＞0如何取，数列{xn}

阅读理解。

     One day Mrs Wilson took Trudy and Ben to go shopping. They went to the supermarket in the new

shopping mall (购物中心).

     "Why do you buy things here, Mum?" Trudy asked.

     "Because they are cheaper than those at the corner store," Mrs Wilson said. "Help me check (检查)

the prices."

     The Wilsons were not wealthy (富有的) and Mrs Wilson was always careful with her money. She

looked carefully at the prices of things. She bought some groceries(杂货) in the supermarket.

When they got home, the children said, "We don't think you saved money by going to the supermarket

there."

     "Of course I did," said Mrs Wilson, "everything was cheap there."

     "We know," said the children, "but we came home by taxi because we had too much to carry. The

cost (花费) of the taxi was more than the money you saved!"

     Mrs Wilson added everything up and found her children were right.

     "Well done," she said, "next time we will do shopping near our home."

根据短文内容，选择正确答案。

1. Mrs Wilson took Trudy and Ben ________.

A. to the supermarket

B. to the zoo

C. to the park

D. to the museum

2. Mrs Wilson bought things in the supermarket in the new shopping mall because ________.

A. goods there had good quality

B. there were many goods

C. goods there were cheap

D. goods there were expensive

3. Which of the following is correct?

A. The Wilsons were rich and they bought a lot of things in the supermarket.

B. The Wilsons were not rich and they bought things in a cheaper supermarket.

C. The Wilsons enjoyed shopping in the shopping mall because it was large.

D. The Wilsons were poor and they seldom went shopping.

4. Mrs Wilson went home ________.

A. by bus

B. by minibus

C. by taxi

D. on foot

5. Mrs Wilson decided to go shopping  ________ next time.

A. in the shopping mall far away

B. in the cheapest shop

C. in the most expensive shop

D. near her home

有一透明的圆柱体是由三块不同折射率的材料A、B、C拼接而成，相互接触处都是光滑平整的平面，如图所示是该圆柱体横截面图，现有一单色光垂直圆柱体轴线从P点射入圆柱体，在界面MO上发生全反射，在界面GO、NG上连续发生两次折射后射出，若该单色光在A、B、C三块材料中的传播速率依次为v_A、v_B、v_C，下列关系式中正确的是

A．v_A>v_B>v_C           B．v_C>v_B>v_A

C．v_B>v_C>v_A           D．v_C>v_A>v_B 

水泵在运行过程中会出现哪些异常声音？

手卫生清洁剂的使用哪些正确（）

A.肥皂应保持清洁、干燥

B.皂液可用清水稀释后使用，以节约成本

C.重复使用的容器应每周清洁与消毒

D.皂液有混浊或变色应及时更换

E.盛放皂液的容器宜为一次性使用

新课程理念下的小学语文教师的角色发生了什么转变？