问题 单项选择题

关于Na+泵的叙述错误的是

A.Na+的活动与温度有关
B.Na+泵在缺氧时活性降低
C.Na+泵循环一次可将2个Na+泵出胞外,3个K+泵入胞内
D.Na+泵的作用是维持细胞内、外离子的不均衡分布
E.当细胞内Na+增多和细胞外K+增多时,可以激活Na+泵

答案

参考答案:C

阅读理解

阅读理解

     London has become a cycle friendly zone after the launch of a new bike hire scheme. It has been

designed to encourage more people to cycle in and around central London.

     So how does it work?First you have to sign up to the scheme to be sent a key. The key will unlock

one of the bikes,  which are kept at docking stations in and around central London. You have to pay

an access fee for the key and then you pay as you go, for the length of time you use the bike.

     Transport for London,  which runs the scheme,  are hoping to have 6,000 bikes and 400 docking

stations in place by the end of the year. The new hire system is hoping to ease congestion(拥挤)in

London and is expected to create up to 40,000 extra cycle trips a day into the city centre. London

Mayor Boris Johnston launched the scheme and said London had been "filled with thousands of

gleaming machines that will transform the look and feel of our streets and become as commonplace

on our roads as black cabs and red buses".

     However,  there have been a few problems since the scheme was launched last Friday. On the first

day some people found they couldn't dock their bikes properly and their usage of the bikes had not

registered. Transport for London did admit they had been expecting a few "teething problems" and have

said they wouldn't charge for the first day as a "gesture of goodwill". Some other people have criticized

the lack of docking stations and locks for the bikes as well as the price it costs to hire the bicycles.

     Despite the comments,  the greenthinking London Mayor still seems very positive about things,  

saying,  "My campaign for the capital to become the greatest big cycling city in the world has taken a big

pedalpowered push forwards."

1. London Mayor Boris Johnston launched the new bike scheme in order to ________.

A. reduce the air pollution of the city

B. encourage the citizens to take exercise

C. deal with the city's traffic problems

D. increase employment opportunities

2. All the following are the problems of the scheme EXCEPT________.

A. the high cost to hire a bike

B. not registering their usage of the bikes

C. not charging for the first day of the scheme

D. docking the bikes properly

3. From the passage we can infer that ________.

A. London Mayor is confident of the scheme

B. the scheme will be cancelled because of the problems

C. all the citizens in London support the scheme

D. the cycling revolution is not successful

多项选择题