为解决水资源短缺问题，中学生能积极参与的是（　　）

求不等式组$\left\{\begin{array}{c}2\left(x-2\right)\le 4x-3\\ 2x-5<1-x\end{array}\right.$的整数解．

填入所缺单词，完成短文。

           like   am   can  wash  girl   soap

    Good morning, my name is Alice. I ____ nine years old. I ____ skip a rope and ride a bicycle. And I can do some washing too. I ____ my dress with the ____. I ____ singing and dancing. I can sing many songs. I am a clever (聪明的)____.

学生问老师多少岁，老师说：“当我象你这么大时，你刚3岁；当你象我这么大时，我已经39岁了．”老师的年龄是（　　）岁．