根据短文理解，选择正确答案。

    If women are mercilessly exploited（剥削）year after year,they have only themselves to blame.Because they tremble at the thought of being seen in public in clothes that are out of fashion,they are always taken advantage of by the designers and the big stores.Clothes which have been worn only a few times have to be put aside because of the change of fashion.When you come to think of it,only a woman is capable of standing in front of a wardrobe（衣橱）packed full of clothes and announcing sadly that she has nothing to wear.

    Changing fashions are nothing more than the intentional creation of waste.Many women spend vast sums of money each year to replace clothes that have hardly been worn.Women who cannot afford to throw away clothing in this way,waste hours of their time altering（政变）the dresses they have.Skirts are lengthened or shortened;neck-line are lowered or raised,and so on.

    No one can claim that the fashion industry contributes anything really important to society.Fashion designers are rarely concerned with vital things like warmth,comfort and durability（耐用）.They are only interested in outward appearance and they take advantage of the fact that women will put up with any amount of discomfort,as long as they look right.There can hardly be a man who hasn't at some times in his life smiled at the sight of a woman shaking in a thin dress on a winter day,or delicately picking her way through deep snow in high-heeled shoes.

    When comparing men and women in the matter of fashion,the conclusions to be drawn are obvious.Do the constantly changing fashions of women's clothes,one wonders,reflect basic qualities of inconstancy and instability （不稳定）?Men are too clever to let themselves be cheated by fashion designers.Do their unchanging styles of dress reflect basic qualities of stability and reliability（可靠）?That is for you to decide.

在生物的所有细胞中，染色体都是成对存在的．（判断对错）

    Mrs White is a housewife. She is always busy in the morning. She gets up early and cooks breakfast. She has two children, Leo and May. Leo is ten years old and May is eight years old. They get up at seven o'clock. Leo makes his bed and washes quickly. May does not make her bed. Her bedroom is often messy. After breakfast, Mrs White takes them to school by car. Then, she goes to the supermarket and buys food for dinner.

    One day, Mr White has a meeting in the office. He does not come home for dinner. Mrs White is busy in the kitchen. Leo and May are waiting for dinner at the table. Leo says:” Dad isn't at home. I'm the head of our family today. I can sit on Dad's chair.” May says,” You should sit on Mum's chair.”

已知函数y=log_ax（a＞0且a≠1），当x∈3，9时，函数的最小值比最大值小1，则a=____．