水在细胞中以结合水和自由水两种形式存在。其中结合水的功能是

二次函数y=ax²+bx+c (a≠0)中的自变量x与函数值y的部分对应值如下表：

则ax²+bx+c=0的解为____ ．

阅读下面短文，在空白处填入一个适当的词，或填入括号中所给单词的正确形式。

    A poor farmer had a friend ____was famous for the wonderful apple tree he grew.    

    One day, his friend ____(give) the farmer a young apple tree and told him to plant it. The farmer was pleased with the gift, but he did not know where____(plant) it.    

    He was afraid that if he planted the tree near the road, strangers would steal the fruit. If he planted the tree in one ____his fields, his neighbors would come at night and steal some of the apples. If he planted the tree near his house, his children would take the fruit.____(final) he planted the tree in his wood. But ____(with) sunlight and good soil (土壤),the tree soon died.    

    Later the friend asked the farmer why he had planted the tree in such____ poor place. "What's the ____(different)? " the farmer asked____(angry). The friend answered, "If you planted the tree in the sunlight, at least ____could enjoy the fruit. Now you not only have robbed everyone of the fruit, but also you have destroyed (毁掉) a good apple tree !"   

口语交际和综合性学习。
      校园里，有不少同学的习惯不好：一次性包装袋随手乱扔，不喜欢的饭菜也挑出来丢在地上，把废纸撕成小片后从窗口抛下，为走近道而从草坪上穿过……为此，学校组织系列教育活动，来矫正同学们的这些不良习惯。

解下列方程（组）：