题目

听录音，补全下面的短文，每空一词。This is a nature park. It's beautiful. There are many in the park. There is ain the park. There is a river inof it. There is aover the river. There are many smallin the park. 答案：【1】plants【2】hill【3】front【4】bridge【5】houses乙二酸二乙酯（D）可由石油气裂解得到的烯烃合成。回答下列问题：（1）B和A为同系物，B的结构简式为_______。（2）反应①的化学方程式为___________，其反应类型为__________。（3）反应③的反应类型为____________。（4）C的结构简式为___________。（5）反应②的化学方程式为______。