题目

This was returned because the person _____ this letter was addressed had died three years ago． A． to whom          B． to which          C． which          D． whom 答案：A化学与生活密切相关，下列说法正确的是A．可通过煮沸水的方法来降低水的硬度 B．食用用“瘦肉精”喂养的猪的肉对人体无害C．人体缺乏维生素C会引起骨质疏松 D．夜间发现家中天然气泄漏，立即开灯查明泄漏原因