①若集合A={x|kx²+4x+4=0}中只有一个元素，则k=1；

②在同一平面直角坐标系中，y=2^x与y=2^﹣x的图象关于y轴对称；

③y=（ $\sqrt{3}$ ）^﹣x是增函数；

④定义在R上的奇函数f（x）有f（x）•f（﹣x）≤0．

“我们唱着东方红，当家作主站起来……”你知道中国人民“当家作主站起来”是（   ）

    In the past, most Chinese families have got one child in them. But recently, the government has relaxed the family planning policy, which means each couple are allowed to have two children. Would you like to have a brother or a sister who grows up together with you?

    Now please write a passage of about 80-120 words to introduce your opinion. The following points should be included:

    ⒈Is it necessary for a family to have more than one child? Give at least two reasons for it.

    ⒉What's the situation in your family? Are you the only child or not? List what makes you happy and unhappy.

    ⒊Give at least two suggestions to the families with two children.