题目

My wife and I moved into our home two years ago. We had a _41 with a lot of rocks. Very often  42 we have flowers, Denise or I would plant some between the rocks, just to add some color to the area. Last summer, I found a tiny little 43 in the yard that I could not 44 identify. I knew I didn’t plant it and Denise said she didn’t either. We decided to let it continue growing until we could find out what it was. Weeks passed and as I made my way back to the 45 plant, it appeared to be a sunflower. I decided to _46 the weeds around it. As I pulled rocks from the area to get to the 有机物A可以通过不同化学反应分别制得B、C和D三种物质，结构简式如图所示．（1）A的分子式是 ； B中的含氧官能团名称是 ．（2）A→C的反应类型是 ；A～D中互为同分异构体的是 （填代号）．（3）由A生成B的化学方程式是： ．（4）C在一定条件下发生加聚反应的化学方程式是： ．