什么是路由器？它主要提供哪些功能？

已知某溶液中只含有OH^-、H⁺、Na⁺、CH₃COO^-四种离子。

（1）若溶液中只溶解了一种溶质，则该溶质是_______________。

（2）若溶液中c(CH₃COO^-)＞c(Na⁺)＞c(H⁺)＞c(OH^-)，则含有的溶质是___________。

（3）若溶液是由体积相等的NaOH溶液和CH₃COOH溶液混合而成，且恰好呈中性，则混合前c(CH₃COOH)________c(NaOH)（填“＜”“＞”或“=”）。

阅读理解。

     Since her husband died, Mrs. Jackson has lived alone in their big old suburban (郊区的) house. The

house was bought by her husband almost fifty years ago.

     For the sake of safety (为安全起见), her son has tried hard to ask her to sell the house and buy a new

and small one in the town, But Mrs. Jackson doesn't like the idea. She says that she has to look after her

husband's old house. But recently she often hears stories about unknown people stealing things around here.

    That was a cold day before Christmas Eve. Around four o'clock in the afternoon, Mrs. Jackson was

enjoying the Christmas music when someone knocked at the door. She heard the sound but didn't move.

Another knock. Who could it be? Mrs. Jackson was a bit afraid. She decided not to answer the door but

keep waiting.

    One minute another minute and yet another minute. Nothing happened and no more knocks, She walked

quietly to the door, and listened. She heard nothing but the wind outside. She slowly unfastened the door

and peeped (窥视) through the crack (小缝). She then gave a surprised cry and threw the door wide open!

At the door she saw a tall, beautiful Christmas tree! In the tree stood a Christmas card with these words:

     Merry Christmas! 

                                                                                                                             Your new neighbor

1. The house bought by Mr. Jackson is ______. [ ]

A. in the town

B. small but new

C. outside the town

D. fifty years old

2. Mrs. Jackson doesn't want to sell the house because ______. [ ]

A. it is almost fifty years old

B. it is big and old

C. she likes to live alone in it

D. her husband left it to her

3. Why didn't she move when she heard the knock at the door? Because ______. [ ]

A. she was enjoying the Christmas music

B. she thought it might be an unknown person

C. it was not her son

D. she hadn't decided to answer the door

4. When she found it was a Christmas tree, she ______. [ ]

A. cried in surprise and pushed the door wide open

B. was very surprised to cry

C. threw the door away

D. went out to stand in the tree

水位计汽水连通管发生堵塞，或汽水门泄漏，对水位计的指示有何影响？

排卵后形成的黄体可分泌的激素是（）

A.黄体生成素

B.卵泡刺激素

C.促性腺激素释放激素

D.人绒毛膜生成素

E.孕激素和雌激素

甲公司是一家家用电器连锁店。在过去的10年中，甲公司一直通过其设在各地的实体店向个人消费者销售家用电器，已经成功建立起很高的信誉和知名度。近期，甲公司管理层通过市场调查发现，日渐兴起的网上购物已经使甲公司失去了～部分订单。甲公司因此开始建立自己的网上购物商城，以期赢得网上购物的订单。甲公司采取的这种战略变革是()。

A．提前性变革

B．反应性变革

C．危机性变革

D．必要性变革