首先簡單的說一下arrive的用法
arrive為不及物動(dòng)詞,即：不能直接跟賓語,如果需要有賓語,得和at 或 in搭配使用.如：
Has he arrived?他到了嗎?（沒有賓語）
He arrived in Beijing yesterday.他昨天到北京的.
I arrived at the airport very early.我很早就到了機(jī)場.
至于arrive后面跟at和in的區(qū)別,可以這樣記憶：
in 表示到達(dá)的地方比較大,如：國家、省、市、鎮(zhèn)等
at表示較小的地方,如：村莊、市內(nèi)的某個(gè)地方（機(jī)場、商店、廣場等）
現(xiàn)在分析你的句子
1.the train always arrives on time.
在本句中,on time是短語,準(zhǔn)時(shí).是時(shí)間狀語.而不是和arrive在一起連用的.
句子意思是：火車總是準(zhǔn)時(shí)抵達(dá).
2.the car always arrives on the farm 這個(gè)是錯(cuò)誤的.不能用on
3.the car always arrives at the farm （arrive at 到達(dá)小地方）
不懂繼續(xù)追問至于arrivein+大地方和arrive at +小地方我倒曉得但是我覺得 the car always arrives on the farm我的理解也還是有理的啊就是把說on the farm 當(dāng)?shù)攸c(diǎn)狀語。況且樓下那位也說我說得對(duì)吶、呵呵， 我查了好幾本詞典～ 我給你列舉麥克米倫Macmillan English Dictionary for Advanced Learners上的用法舉例吧。我只是覺得從來沒有見過用arrive on 表示地點(diǎn)，就是用也應(yīng)該是非常罕見。 1. The verb arrive is never used with the preposition to: ✗ He meets them at an inn before they arrive to the house. ✓ He meets them at an inn before they arrive at the house. Arrive can be used with at or in: ▪you arrive at a building (such as an airport or restaurant)例句：…the scene in which Robyn arrives at the factory for the first time ▪you arrive in a geographical location (such as a city or country) 例句：A delegation of senior French ministers will arrive in London today.▪you can also use arrive at in a figurative way, meaning ‘to reach a particular goal or point in a process’ Quite independently, we all arrived at the same conclusion. The court will arrive at a final decision next week.Note that with the word home, no preposition is used: ✗ When they finally arrive at home, all they want to do is sleep. ✓ When they finally arrive home, all they want to do is sleep.在用法中并未涉及on.我覺得，你不要在糾結(jié)這個(gè)問題了，我們?cè)趯W(xué)習(xí)語言，不是創(chuàng)造語言。只是用來和別人溝通罷了，你非要說可以，也許過很多年，很多人都在用arrive on了個(gè)人覺得還是不要用on·····希望幫到你