When someone or something reaches a place, they arrive there.
When the bus reached High Holborn, Tony rang the bell and they jumped off together.
Collins Cobuild English Dictionary for Advanced Learners pp.1274~5
由此可見，reach（=抵達= get to）的主詞可以是物的。
The letter reached me the day before yesterday.(本句無法將原動詞reach改寫成被動態，因語意不通)
= I received the letter the day before yesterday.
= The letter was received by me the day before yesterday.
(He probably mailed me the letter a week ago.= The letter was probably mailed to me a week ago.)
The letter was reached me the day before yesterday.這樣寫是錯誤的。如果用被動的reach來寫，怎麼還能再有一個受詞me呢?被動態的句子裡，主詞letter就是動詞reach在邏輯上的受詞。此外，就算把me拿掉也是不通的。這跟reach這個動詞的用法有關。
He can be reached at this number.＝打這個號碼就可以跟他連繫上。
Men are often reached by flattery. =人常為恭維的話所動。
被動語態要從受詞的角度去考慮, 而不是從主詞的角度. 所以你以"信"的角度來看, 如果要用被動, 那它的身分是受詞, 所以會有另一個"主詞"來做這個動作:
Someone sent/delivered/mailed/brought the letter to me. =>
The letter was sent/delivered/mailed/brought to me.
可是reach是"到"的意思, 即使是中文也沒有"被到"的說法, 英文也沒有. 這個動詞強調的是[從有距離變成沒有距離]的狀態變化, 所以不用被動.
reach vt.及物動詞 釋義1.到達 2.(餘略) 例1. The letter reached me the day before yesterday. 例2. I hope this letter reaches you. (我希望你能收到這封信。) 例3. Your letter never reached me. 例4. The news of his death soon reached every part of the world. 例5. The village is easily reached by bus. (乘坐公共汽車很容易到達那個村莊。)
The letter=it=pronoun used as arbitrary subject (decided by random)as a that thing,group,idea already mentioned etc.
reach= v.= to arrive at or come as far as; get to; often after much time or effort;
Further eg:-After several changes of address, the letter finally reached me.----past tense., which is the form of a verb that shows the act or state described by the verb happened or existed at some time before the present moment.
eg:-I reached the end of the short book.
eg:-The legislative council news only reached me two days ago.
eg:-She has reached the age of 25 !
eg:-The sales of iphone7 has reached record level in Korea.
eg:-The two sides failed to reach agreement in the Council.
eg:-The snail reached the vegetables on the ground.
eg:-The ship reached to the horizon two days ago.
eg:-The ladder won t reach as far as the outside window.
eg:-The ladder reached down to the road !
eg:-Could you please reach the letter from the mailbox ?!
eg:-The monkey reached out for the fruit two days ago !?
eg:-The letter reached me two days ago.= past tense.