问题 单项选择题

鉴别室速与阵发性室上速最有力的证据是()

A.QRS波群宽大畸形的程度

B.是否存在房室分离

C.心室率的快慢

D.静脉应用普罗帕酮是否可终止

E.对迷走神经刺激的反应

答案

参考答案:B

解析:下列心电图表现提示为室性心动过速:①室性融合波;②心室夺获;③房室分离,如心室搏动逆传,P波与QRS波群相关,房室分离消失,可出现1:1室房传导或2:l室房传导阻滞;④QRS波群时限超过0.14s,电轴左偏;⑤QRS波群形态,当表现为右束支传导阻滞时,具有以下的特征:V1导联呈单相或双相波(R>R′);V6导联呈rS或QS;亦可呈左束支传导阻滞型;⑥全部胸导联QRS波群主波方向呈同向性:即全部向上或向下。

阅读理解

London Underground

The world’s first subway was built in London in 1863. At the time,the government was looking for a way to reduce traffic problems in the city of London. The poor areas of the city were so crowded with people that it was almost impossible for horse carriages to get through. The city officials were interested in trying to make it possible for workers to live outside of London and travel easily to work each day. If people had a cheap and convenient way that they could depend on to go to and from work, they would relocate their homes outside of the city. This  would  help ease(减轻) the pressure of too many people living in the poor parts of London. From these problems,the idea of the London Underground,the first subway system,was born.

The plans for building the Underground met with several problems and delays,but the fast track was finally opened in January 1863. A steam train pulled the cars along the fast underground track which was 6 kilometers (3.7 miles) long. About 30,000 people got on the subway the first day. Riders were treated to comfortable seats (standing up while the train was moving was not allowed), and pleasant decorations inside each of the cars. However, the smoke from the engine soon filled the air in the tunnels with ash and soot(煤灰), as well as chemical gases. Fans had to be put in the tunnels later to keep the air clean enough for people to breathe. Even with its problems,riding in the Underground did catch on. It carried 9 million riders in its first year.

小题1:How did the London Underground solve the smoke problem?

A.It made the tunnels larger.

B.It put fans in the tunnels.

C.It cleaned the chemical gases in the tunnels.

D.It reduced the number of passengers riding in the train.小题2:What led the British government to build the London Underground?

A.Traffic jams and pollution.

B.Population and pollution.

C.Overcrowding and traffic jams.

D.The poverty and subway problems.小题3:Which of the following is TRUE?

A.To relocate the workers’ homes outside London,the government built the subway.

B.There were so many problems and delays that in 18th century the first subway opened.

C.The subway greatly eased the pressure of traffic.

D.There were not enough seats for the passengers the first day the subway opened.小题4:The underlined phrase “catch on” most probably means “______”.

A.be troublesome

B.become popular and fashionable

C.keep up with

D.seize

单项选择题