题目

 ---What do you think of your headmaster? ---            .        A. I like him                                                     B. He is not very tall             C. He often smiles                                            D. He is very kind 答案：D水淹导致植物死亡的主要原因是 A．土壤溶液浓度过低，细胞吸水过多胀破细胞壁  B．土壤中矿物质溶于水后达到毒害作用的浓度 C．厌氧呼吸产生过多的CO2对根细胞有毒害作用  D．根部严重缺氧，造成厌氧呼吸产生过多的酒精