题干

在一个口袋中有个完全相同的小球,把它们分别标号为,随机摸取一个小球然后放回,再随机地摸取一个小球。
【小题1】(1)采用树状图法(或列表法)列出两次摸取小球出现的所有可能结果,并回答摸取两球出现的所以可能结果共有几种;
【小题2】(2)求两次摸取的小球标号相同的概率;
【小题3】(3)求两次摸取的小球标号的和等于的概率;
【小题4】(4)求两次摸取的小球标号的和是的倍数或的倍数的概率。
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    People often say that the Englishman's home is his castle. They mean that the home is very important and personal to him. Most people in Britain live in houses rather than flats, and many people own their homes. This means that they can make them individual(个体的): they can paint them, and change them in any way they like. Most house have a garden, even if it is a very small one, and the garden is usually loved. The house and the garden are the private(私人的) space of the individual.

    People usually like to mark their space. Are you sitting now in your home or on a train? Have you marked the space around yourself as yours? If you are on the train you may put your coat or small bag on the seat beside you. If you share a flat you may have one corner or chair which is your own.

    Once I was travelling on a train to London. I was in a section for four people and there was a table between us. The man on the space on my side of the table didn't notice me at all. I was angry. Maybe he thought that he owned the whole table. I had read a book about non-verbal communication, so I took various papers out of my bag and put them on his briefcase! When I did this he stiffened and his eyes nearly popped(瞪出) out of his head. I had invaded(侵犯) his space! A few minutes later I took my papers off his case in order to read them. He immediately moved his case to his side of the table. Of course, it is possible that he just wanted to be helpful to me!

    If you are visiting another country you may feel that you don't have any private space. Hotel rooms look much the same in every country in the world. All day long, you share public spaces with other people. You see the local people in their private spaces and you feel lonely and "outside". Local people can create their private spaces by talking about things you don't know about. And you even feel that they like you to be outside them so that they will enjoy being inside even more! This is one of the difficulties of being a traveler! But if you understand it then it helps you. Haven't you enjoyed being part of a group and "owning" a bit of space?