看这里！山东淄博2020年专升本考试报名流程早知道！

We first think of the traditional or nuclear family．This is a two-generation family,the father and the mother and their own children．Most couples wanted to have four children,two boys,two girls.
Some nuclear families,however,may add one or more grandparents to come to live with them,that is three generations．This kind of family with grandparents,parents,and grandchildren is called an extended family．This family type was not very common during the later half of the twentieth century,but it's becoming more common now as an elderly grandparent moves in to live with a son or daughter．This is more possible now that American homes have become larger．What is interesting,however,is that after the grandchildren move out of the home and start their own families,this extended family shrinks back to a nuclear family,with just two generations again living together,a grandparent and parents,with the grandchildren coming only for occasional visits．
Now,the fatherless or motherless family is one kind of what we call a single-parent family．In the fatherless family it's just the mother and her children．As I said,this can be the result of the husband's death,of an unmarried mother,of a separation or divorce．There are also a growing number of motherless families--where the father raises the children,for any of the same reasons．A motherless family may also be fatherless,but still a family with one adult．This is becoming more common in the big cities where a grandmother will raise her daughter's children while the daughter goes elsewhere to work.
One other new kind of family is becoming increasingly more common．A single parent with one or more children will marry again．Perhaps the other parent is also a single parent．Together they will start what is called a blended family,which blends together or combines the children from two other families.

What is true to the fact in America?

A.There are more and more members in a famil
B.There are less and less members in a famil
C.There is an increasing number of grandparents who refuse to look after their grandchildre
D.There is an increasing number of grandparents who live separately from their childre

A.是发散的
B.等于1
C.等于0
D.等于－1

心电图PP间隔明显延长，与基本窦性PP间隔无倍数关系，首先考虑的诊断是( )

A．窦性停搏
B．房性早搏
C．二度房室传导阻滞
D．一度房室传导阻滞
E．室性早搏

Stress makes a person want to stop whatever they are doing,try to relax,and become calm again．Too much stress results in physical,emotional,and mental health problems.
There are numerous physical effects of stress．Stress can affect the heart．It can increase the pulse rate,make the heart miss beats,and can cause high blood pressure．Stress can affect the respiratory system．It can lead to asthma．It can cause a person to breathe too fast,resulting in a loss of important carbon dioxide．Stress can affect the stomach．It can cause stomach aches and problems digesting food．These are only a few examples of the wide range of illnesses and symptoms resulting from stress.
Emotions are also easily affected by stress．People suffering from stress often feel anxious．They may have panic attacks．They may feel tired all the time．When people are under stress,they often overreact to little problems．For example,a normally gentle parent under a lot of stress at work may yell at a child for dropping a glass of juice．Stress can make people angry,moody,or nervous.
Long-term stress can lead to a variety of serious mental illnesses．Depression,an extreme feeling of sadness and hopelessness,can be the result of continued and increasing stress．Alcoholism and other addictions often develop as a result of overuse of alcohol or drugs to try to relieve stress．Eating disorders,such as anorexia,are sometimes caused by stress and are often made worse by stress．If stress is allowed to continue,then one's mental health is put at risk.
It is obvious that stress is a serious problem．It attacks the body．So,reduce stress:stop the world and rest for a while.

Stress can affect the respiratory system by__.

A.decreasing the pulse rate
B.a loss of carbon dioxide
C.causing breathing problems
D.causing asthma