阅读理解

    I'm Amy. I have a new schoolbag. It's black and white. It looks like a panda. It's big. The yellow one is mine, too. It's too small for me. What's in my schoolbag? A pencil-box and some books. But not all the books are mine. I'm new here. The storybooks are Zhang Peng's. This English book is his, too. Lucy and Lily are twin sisters. The science book and Chinese book are theirs.

物理变化与化学变化最本质的区别是有没有____ 生成．

电报的发明者莫尔斯以前是个画家，一次偶然的机会是他对魔术师的表演产生了“能不能用电流传递信息”的疑问此后他从事电学研究，经过5年的学习和探索，终于发明了电报机，从莫尔斯可以看出（    ）