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问题 单项选择题

窦性心律的心电图表现必须具备

A．各导联均可见P波，P波在Ⅰ、Ⅱ、aVF、V5、V6导联应直立，在aVR导联应倒置，PR间期应≥0.12秒
B．各导联均可见P波，P波在Ⅰ、Ⅱ、aVF导联应倒置，在aVR导联应直立，PR间期＜0.12秒
C．各导联可见倒置P波，PR间期≥0.12秒
D．各导联均可见P波，在I、aVL导联倒置，aVR导联直立，PR间期≤0.12秒
E．各导联P波消失，RR间期正常、相等

答案

参考答案：A

解析：[考点] 窦性心律心电图特征

[分析]： 窦房结是心脏正常窦性节律的起搏点，冲动在窦房结形成后，先传至右心房，然后经房间束传入左心房。由于心房除极波 (P波)的除极瞬间综合向量总是自右上向左下方向扩展，因此在其除极开始处(右上)放置电极(aVR导联)其P波方向总是向下的(倒置)，在其除极方向处(左下)放置一电极(Ⅰ、Ⅱ、aVF导联)，其P波方向总是向上的(直立)；窦房结发出的冲动经心房传至房室交界区，再经希氏束、束支、浦肯野纤维至心室肌，完成一次心动周期，由心房传至心室，最快传递速度须在0.12秒及以上，故PR间期应≥0.12秒。

完形填空
Have you ever asked yourself what makes people successful? If you look around and talk those who are very successful, you will see that they all   ____   certain qualities which have proved  ____  for their success.
It is evident that successful people are those who act. When they find something needs to be done, they just do it instead of waiting. They believe that   ____  is taken, not given. They    ____  immediately what has to be done and then do it with   ____， thus strengthening their reputation.
Successful people are  ____  about the things they do, especially when they  ___ what  they  are doing. They are motivated by their own  ___  and the joy they get from doing their work. They work hard  ____  when no one is watching and they throw themselves into their work.
They do not   ____  failure. Failures and disappointments in life are  ____. It is failure that  teaches us much more than success. Successful people pick themselves up after a fall and try  again with more determination and   ____  and learn from each failure. They   ___  with those  they can learn from and enjoy the company of those who  ____  their achievement.
Having good IQ often gets a person what he wants but it's   ____  the EQ that keeps him  there and helps him enjoy a high reputation. Successful people are polite to everyone and treat  others with respect. By giving respect to others, they  ____  respect for themselves.
Another important   ____  of successful persons is that they never complain. It's better to  praise others and win favor with them. So instead of complaining about a situation, successful  people always try to solve it.
To put it   ____， take action and be enthusiastic. Do not be afraid to fail,  ____ get up and  start again. When you do so, success will be just  ____  the corner.
小题1:
A．improveB．raise
C．testD．possess
小题2:
A．vitalB．individual
C．personalD．mental
小题3:
A．devotionB．responsibility
C．authorityD．administration
小题4:
A．sighB．show
C．weighD．hope
小题5:
A．pleasureB．honor
C．adventureD．behavior
小题6:
A．enthusiasticB．characteristic
C．energeticD．authentic
小题7:
A．bring inB．believe in
C．call inD．join in
小题8:
A．effortB．satisfaction
C．conditionD．value
小题9:
A．justB．right
C．onlyD．even
小题10:
A．representB．expect
C．fearD．want
小题11:
A．apparentB．uncomfortable
C．unavoidableD．urgent
小题12:
A．commitmentB．arrangement
C．movementD．achievement
小题13:
A．progressB．work
C．associateD．celebrate
小题14:
A．congratulateB．appreciate
C．attemptD．choose
小题15:
A．especiallyB．totally
C．naturallyD．really
小题16:
A．payB．receive
C．requireD．promise
小题17:
A．qualityB．identity
C．abilityD．reality
小题18:
A．honestlyB．firmly
C．shortlyD．deeply
小题19:
A．soB．and
C．orD．but
小题20:
A．inB．at
C．withinD．around
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单项选择题

材料在承受外力作用的过程中，必然产生变形，撤除外力的作用后，材料的几何形状只能部分恢复，而残留一部分不能恢复的变形，材料的这种性能称为( )。

A．韧性
B．弹性
C．塑性
D．脆性
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