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    Friendship is a kind of human relationship. It is a human instinct to make friends. When ____ trouble, we need friends to offer us help, support and encouragement. With success achieved, we also need friends to share our joys.
    Friendship is also one of the greatest ____ (pleasure) that we can enjoy. It implies loyalty, cordiality, sympathy, affection and readiness to help. No man can make ____ most of his life  without ____ (careful) and conscientiously（认真地）struggling to win the right kind of friends as he ____ (go) along.
    Knowing how ____ (value) friendship is, we should be very careful in making friends. Real friends are those who have good character, superior ability and kindness of heart. Real friends can share all our sorrows and double all our joys. ____making friends, we should take care ____ (select) those who have such fine qualities. We should forgive their failures and do our best to help them. In short, when we have established friendship, we ought to cherish and treasure it ____ means of words and deeds. Only thus, can we develop real friendship and keep the sacred lamp of friendship ____ (burn) all of life.

命题“若a＞b，则a+c＞b+c”的否命题是（   ）

如表是小滨制定的食谱单，为使营养均衡，在“你的补充”栏可以选填的食物是（   ）

主食	米饭、馒头
菜肴	炒鸡块、红烧鱼、油炸花生米
饮料	牛奶
你的补充

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                                                                                                     狮子和老鼠（《 伊索寓言》）
      有一天，一头大狮子在太阳下睡觉。一只小老鼠经过时碰到了它的爪子，把它惊醒了。大狮子张嘴准备吃它，小老鼠哭道：“哦，别吃我，请让我走吧，先生！有一天也许我会报答你的。”
      狮子在心里冷笑，小小的老鼠怎么可能帮自己呢？但它是一只好心肠的狮子，就把老鼠放走了。
      不久以后，狮子被一张网网住了。它使出全身力气使劲挣扎，但网太结实了，它大声吼叫，小老鼠听到了它的吼声，就跑了过去。
     “别动，亲爱的狮子，我来帮你。我会把绳子咬断的。”
      老鼠用它尖锐的小牙齿咬断了网上的绳子，狮子从网里挣脱了出来。
     “上次你还耻笑我呢！”老鼠说，“你觉得我太小了，没法为你做什么事。但你看，一只可怜的小老鼠救了你的性命。”

如图所示，如果要使灯L₁与L₂并联，则应该闭合开关____，断开开关____；同时闭合开关____是不允许的.