reason/ˈriːz(ə)n/
n.1. 原因;理由;动机The reason she was ill was that she had eaten bad meat.她生病的原因是她吃了变质的肉。
The reason for this is that this plane is also a bicycle.其原因是,这架飞机又是一辆自行车。
2. 理性;理智;道理;判断力There's a great deal of reason in his advice.他的忠告极有道理。
There are reasons for this great interest in the ideas, feelings, and actions of youth.对年青人的思想、感情和行动发生这样巨大的兴趣,自有它的道理。