答案:[解析]考查reason的用法。如果先行词reason在从句中作主语或宾语时,则用that或which,不用why。在本句中,reason在从句中做宾语。而在其它情况下用why。例如:The reason why he died young was his inattention to health. 他早死的原因是不注意自己的身体。而reason后用for时结构为:the reason for sth./doing sth. 如:Give me the reasons for your going. 告诉我你去的动机。