1 myself 意为我自己——I am teaching myself French.这里做宾语.
——I myself wrote the report.这里做同位语——I'll talk to him myself.这里用作介词结构=I‘ll take to him by myself.简单来说,myself可做宾语,同位语,意为我自己.也可相当于介词结构by myself ,意为（通过）我自己.而by myself只可做介词结构,比起myself做介词结构更具有强调性.2 it指代上面提到的物体（同一个） that 与one 相近,不过意为那个,那,是远指.（那） one可以代替与前面同类不同一的事物；可以代替某类事物中的任何一个（任意一个）
——Do you haven`t an English-Chinese dictionary?--- Yes,I have it.
——The language used in advertisements differs from one used in ordinary readings——The environment in this faraway town is as pleasant as that in the coastal city (that常用于指天气,环境 ,且常用于有比较意义的指代中）3 ago和before 都可作为“在……之前” 当两者译为“在……之前”,ago用于直接引语,before只能用于间接引语.——I bought this book three days ago——He tolds me that he had bought this book three days before.
