[不定项选择题]腺苷
A.终止心房扑动
B.终止心房颤动
C.终止室上性心动过速
D.终止尖端扭转型室性心动过速
E.终止非阵发性交界性心动过速

[不定项选择题]腺苷
A.终止心房扑动
B.终止心房颤动
C.终止室上性心动过速
D.终止尖端扭转型室性心动过速
E.终止非阵发性交界性心动过速

[不定项选择题]通过激活腺苷酸环化酶产生平喘作用的药物是
A.氨茶碱
B.异丙托溴铵
C.色甘酸钠
D.酮替芬
E.β受体激动剂

[单选题]腺苷脱氨酶缺乏症是由于腺苷脱氨酶的( )
A.基因缺陷引起
B.表达受阻遏引起
C.活性被抑制引起
D.变性引起
E.化学修饰引起

[单选题]酶的可逆共价修饰中，酶的腺苷酰化和去腺苷酰化位点通常在酶的哪一种氨基酸残基上（　　）。
A.天冬氨酸
B.脯氨酸
C.赖氨酸
D.酪氨酸

[不定项选择题]共用题干 American Dreams

There is a common response to America among foreign writers:the US is a land of
extremes where the best of things are just as easily found as the worst.This is a cliché（陈
词滥调）.
In the land of black and white,people should not be too surprised to find some of the
biggest gaps between the rich and the poor in the world.But the American Dream offers a
way out to everyone.________(1)No class system or government stands in the way.
Sadly,this old argument is no longer true.Over the past few decades there has been a fundamental shift in the structure of the American economy.
The gap between the rich and the poor has widened and widened.________(2)
Over the past 25 years the median US family income has gone up 18 percent.For the
top 1 percent,however,it has gone up 200 percent.Twenty-five years ago the top fifth
of Americans had an average income 6.7 times that of the bottom fifth.________
(3)
Inequalities have grown worse in different regions.In California,incomes for lower
class families have fallen by 4 percent since 1969.________(4)This has led to an
economy hugely in favor of a small group of very rich Americans.The wealthiest 1 percent
of households now control a third of the national wealth.There are now 37 million
Americans living in poverty.At 12.7 percent of the population,it is the highest percentage
in the developed world.
Yet the tax burden on America's rich is falling,not growing.________(5)There
was an economic theory holding that the rich spending more would benefit everyone as a
whole.But clearly that theory has not worked in reality. ________（5）
A.Nobody is poor in the US.
B.The top 0. 01 percent of households has seen its tax bite fall by a full 25 percentage points since 1980.
C.For upper class families they have risen 41 percent.
D.Now it is9.8 times.
E.As it does so,the possibility to cross that gap gets smaller and smaller.
F.All one has to do is to work hard and climb the ladder towards the top.