①意识是人脑对客观存在的正确反映

②先进意识具有超越时代和历史条件的特性

③意识因其创造性而具有超前性

④意识因其能动性而具有指导性

材料：二里头文化三期陶器纹饰拓本

C

    One of the easiest ways to keep fit is to do jogging. Jogging is the name for a very gentle(舒缓的) running-it is just a little faster than walking.

    Start slow joging 20 meters , then walk 20 meters. Little by little , if you are not feeling very tired , you may do more jogging and less walking . Finally , jog the whole way . It will be easy for you to start jogging for 15 minutes twice a week , slowly, increase this to 20—30 minutes every day .The longer you join in jogging , the more you enjoy it and the healthier you will become . Some people like jogging alone , and others enjoy doing it with friends . Jogging in groups makes more people keener(热心的)，because you just can not stay in bed while there is a group of friends waiting outside.

    If you want to start jogging , prepare a pair of comfortable shoes and a determined mind.

（1）解方程组：$\left\{\begin{array}{c}2x+y+z=-1\\ 3y-z=-1\\ 3x+2y+3z=-5\end{array}\right.$．

（2）若a^x=10，a^y=2，求a^2x﹣y的值．