已知函数，则下列结论正确的是 （   ）

A：，为奇函数且为上的减函数

B：，为偶函数且为上的减函数

C：，11 to, but he had formed a habit. Habits can be hard to 12.

    In fact, if we repeat any behaviour 13 enough, it becomes a habit. But some habits can work in our favour, such as 14 attitudes and healthy ways of life. Our habitual attitudes and behaviour can either 15 us or hinder(阻碍) us.

    Is there behaviour or an attitude you would like to make into a 16? Then reinforce (强化) it by  17 it at every opportunity.

When it comes to habits, 18 may not make perfect. But practice will certainly form 19 behaviour. Your habits will form who you are. So form the habits that are 20to you and let them mold (塑造) you into the person you want to be.