rule(r)
1.according to rule是“依照规则（不是随便）地”,according to the rule是“依照这条规则地”。
2.by rule直译作“依照规则地”，实际有“呆板地”或“机械地”的意思。例如：We cannot speak by rule. （我们不能呆板地说话。）
3.as a rule指经常的事，不指一次的事，如可以说As a rule he came twice a week，不可说As a rule he came at eight o'clock that morning。前一句里的As a rule可以改作Usually。后一句里的As a rule该改作As usual。
4.under French rule等表达方式里没有the。但What do you think of the French rule? 等表达方式里习惯有the。
5.说“尺”用rule和ruler都可以，用rule着重在量长短，用ruler着重在划线。
