什么是化学变化？
参考答案：
物质变化时生成了其它物质的变化叫化学变化。
—Will you please _______ it to me on Tuesday?
—What about Saturday? My computer doesn't work well these days. [ ]
A. post
B. give
C. email
D. bring
简述带煤气搬眼作业程序？
