i have arrived by train中的arrive 为什么用完成?而不用be there?

i have arrived by train中的arrive 为什么用完成?而不用be there? ‘I’ve just arrived by train中的 i have just arrived by train.为什么有have.它起什么作用 I've arrived by train为什么不是I arrived by train? I have just arrived by train这里为什么要用现在完成时呢 表状态情绪感觉精神活动的动词,不用现在完成时对吗～I have just arrived by train 这句话对吗 连词成句he by train arrive have I have been there by train.I have ______get. i think he have been arrived?arrive不是不及物动词吗?怎么后面不用接介词呢? there,10:00,I,do,have,to,arrive,by连词成句 ‘I have just arrived by train,’she said.变成间接引语 这两句英语的区别?I arrived by train.I've arrived by train.