There is an old Chinese saying, “If someone gives you a little drop of water, you should return a spring of water." That means if someone helps you a bit, you should remember it and thank them gratefully(感激的）in return.

       We should live in a world of gratitude. We should prove it with actions, not just words. We thank people who hurt us, because they teach us important things. We thank people who give us up, because we learn how to be independent. We thank people who selfish(自私的）, because we learn the importance of being kind. Of course, we should thank people who help us. We should thank people who teach us. We should thank people who care about us.

      We thank our parents. They work hard all the time in order to give their sons and daughters a better life. They cook meals for us, they do the chores for us, they always give us food and clothes, they teach us what is right and what is wrong.

      We thank our teachers who give us dreams. They teach us a lot of things but they ask for nothing from us. We are well-educated of them.

     There are a lot of people that we should be grateful to in our life. We should find a way to thank them.

 生活中某些物质的pH近似为：西瓜汁5.8、苹果汁3.1、泡菜3.4、鸡蛋清7.6，其中酸性最强的是（　　）

补充成语

____颜____色　  冥____苦____　____工____匠

将曲线$y^2=4x$  按$\phi :\left\{\begin{array}{c}{x}^{\text{'}}=2x\\ 2y^{\text{'}}=y\end{array}\right.$  变换后得到曲线的焦点坐标为(   )