买五本《童话故事》和一本《少儿百科全书》，50元钱够吗？

向Mg(NO₃)₂和Cu(NO₃)₂的混合溶液中加入过量的Zn粉，充分反应后过滤、滤纸上的物质为（  ）

    My uncle is a farmer. He has ninety 1trees on his farm. My uncle and my2can't pick(采摘) all the apples in fall(秋天).3 they ask my parents and me to 4 them every year. It's Sunday. My parents don't go to5and I don't go to school. So we'll go to the6. We get up early(早) in the 7 My mother is in 8 old clothes. My father buys many kinds of food for my uncle's 9in a shop. She likes them very much. My uncle and aunt 10 us many apples, too. I like to work on the farm.

请问：甲图设计这个实验的目的是____，此实验中让小球从同高度滑下的目的是____，这个实验中得到的结论是____。实验中木块移动的距离反映____，这种方法叫做____。这个实验不用木块____（选填“可以”“不可以”）得出实验结论。图乙中研究对象是____，泡沫塑料的作用是____。

爱动脑筋的小明认为乙图中用小车代替小球实验更好，理由是____，