已知f(x)=(x+2)2(x≥0),又数列{an}(an>0)中,a1=2,这

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问题:

已知f(x)=(
x
+
2
2(x≥0),又数列{an}(an>0)中,a1=2,这个数列的前n项和的公式Sn(n∈N*)对所有大于1的自然数n都有Sn=f(Sn-1).
(1)求数列{an}的通项公式;
(2)若bn=
an+12+an2
2an+1an
(n∈N*),求证
lim
n→∞
(b1+b2+…+bn-n)=1.
考点:数列的极限
题型:解答题

下列关于胶体和溶液的叙述正确的是(  )

A.溶液呈电中性,胶体带电

B.溶液中溶质微粒一定不带电,胶体中分解质微粒带有电荷

C.通电后溶液中溶质微粒分别向两极移动,胶体中分散质微粒向某一极移动

D.胶体是一种稳定的分散系

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    Lucy       a wide mouth?   —No, she doesn’t.

A. Do. has              B. Does,have          C. do,have

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将一个偶然的事件中取得的信念不恰当地用于引用于其它情况。这种负性自动想法称为()

A.主观臆断

B.以偏概全

C.过度引申

D.夸大

E.非黑即白的绝对性思考

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-There is a very special wolf that lives in Africa. They are actually called, the African wild dog, or painted dogs.

These animals live in open woodlands. or in the plains of Africa. Today, however, most of the animals can be found in eastern or southern Africa. These animals are beautiful. They have rounded ears instead of pointed like most dogs, and they have four toes (脚趾) on each of their feet, also a unique characteristic because other dogs have five. Their fur is always different from each other. The fur is usually a combination of black, brown, red, and white, and sometimes even yellow. No wonder they’re called the painted wolf.

The African wild dog is a very social animal. They live in groups and have numbers from five to about twenty. The members of a group are always very close to one another. They communicate in their own language or body language. When someone is very old or sick, the others will help, and they are willing to share the food with elders and with those who are weak, which is what we should learn from.

The family does everything together, from raising young, to sleeping together, to hunting. When they hunt, they work together using team work to kill animals that are larger than them.

They sometimes hunt farm animals. This is unfortunate, because both poachers (偷猎者), and people who own farms shoot the painted dogs who are just trying to survive.

Before, there used to be many large groups throughout the land, but now the African wild dog is very rare. They are also losing their population because of their own loss of habitat thanks to human’s farming and forest cutting.

小题1:Why do African wild dogs get the name “painted dogs” ?

A.They all have colorful fur.

B.The dogs in the same group are of different colors.

C.Artists love to paint them in different colors.

D.None of them has the same color.小题2:According to the author, what should we learn from African wild dogs?

A.They always do everything together.

B.They are always very close to one another.

C.They help the sick, the elderly and the weak.

D.They communicate in their own language.小题3:Which of the following is NOT the reason why African wild dogs are becoming very rare?

A.Poachers kill some of them.

B.They are short of food sometimes.

C.They are losing their habitat.

D.Farmers shoot some of them.小题4:Where could this passage probably be found?

A.The Travelers

B.Fashion Weekly

C.Animal World

D.Star Magazine

题型:解答题

如果触电者伤势严重,呼吸停止或心脏停止跳动,应采取()和()急救措施。

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