数列a，a，a，a…，（a∈R）必为（　　）

    Wang Fei，a Chinese student，and Mary，an American student studying Chinese in China，were in a supermarket．They saw a young man walking down the stairs．In his hurry，he missed the last two steps and fell onto the ground．He tried to stand up while people around him laughed．Luckily，he seemed to be OK．

    Mary found Wang Fei smiling a little and was not happy about it. “Tell me, Fei, how could people laugh when someone fell like that? Why didn't they go up and ask him if he was hurt?”

    Wang Fei said, “Because they knew he wasn't hurt too much.”

    “But I still don't understand．A fall is a fall．In my culture, people would never laugh!”

    This is an example．The Chinese and the westerner will think and act differently when seeing such a thing．Chinese people are used to laughing or smiling．Very often the person who is in embarrassing（困窘的）situation would also laugh or smile to get out of it．However，if someone gets hurt seriously，it will not be a laughing matter any more．People will help him or her instead．

    But，in that case，a westerner will rush over and help the person get up．If a westerner falls，he or she，like a Chinese person，may try to make a joke if he or she is not hurt．If two close friends are walking together，and one falls but clearly isn't hurt，a common joke is to say “Have a nice trip”．

    So different people have different habits and different countries have different cultures

      A poor woodcutter and his wife lived in the forest in a small hut.   1 was so small that there was space only for him and his wife to sleep.
      One cold night, somebody knocked 2 the door. The woodcutter asked his wife  3the door and let the stranger in. She said, “ But there is no space.” The man laughed 4 said, “ Two can sleep well, three can sit.” And then the woman opened the door. The stranger5 to come in, and they all sat telling stories to each other.
     Then came 6 knock. The woodcutter told the stranger, “Friend, open the door.” And the man said, “But there is no space.” The woodcutter said, “If three persons can sit comfortably, four persons can sit a little7 than before.”
The stranger opened the door, and a man entered. Suddenly, a strange knock 8 did not seem to be human's! The woodcutter said, “Open the door. I know who 9.  It is my donkey.”
    Everyone said, “  10is the donkey going to stand?” The man said, “Right now we are sitting, when the donkey comes in, we will all stand.”

【甲】

    “简·爱！——简·爱！”他只知道叫唤着。

    “我亲爱的主人，”我回答说，“我是简·爱，我终于找到你了——我回到你身边来了。”

    “真的是吗？——真的是有血有肉的简？我那活生生的简？”

    “你已摸到了我，先生——你正搂着我，而且搂得紧紧的。我可不是像尸体那样冰冷，也不像空气那样虚无缥缈，是不是？”

    “我活生生的宝贝！这的确是她的四肢，这的确是她的五官。不过我受了那么多苦以后，不可能有这么大的幸福了。这是梦。是我夜里常做的那种梦，我梦见像现在这样又把她紧紧搂在怀里，吻她——我觉得她是爱我的，相信她绝不会离开我。”

    “从今天起，先生，我永远不会离开你了。”

（选自《简·爱》，商务印书馆，宋兆霖译）

【乙】

    “简·爱！——简·爱！”罗切斯特激动得只能说出这几个字。

    “罗切斯特，我是简·爱，我回来了！”

    “我不是又在做梦吧？我做过很多这样的梦，梦见我的简回到我的身边。可是醒来后，她就像空气一样消失了，她不会再消失了吧？”

    “不会了，先生，我要永远留在你身边，从今天起。”

（选自《简·爱》，吉林文史出版社，李勋译写）

已知函数y=lg$\frac{1+x}{1-x}$的定义域为集合A，集合B=（a，a+1），若B⊆A，求实数a的取值范围．