問：貴欄說「off of一般算是較隨便的說法，嚴肅寫作會把of畧去」，並舉馬克．吐溫句子為例：I'd borrow two or three dollars off of the judge（我會向法官借兩三塊錢）。但這一句的off of似應改為from，不能只刪去of一字，對嗎？
答：查英文介系詞用法專書Collins COBUILD English Guides: Prepositions，borrow條下有注釋說：向人借錢或借其所有的東西，可說"to borrow money or a possession from someone or off someone"，例句如下：He was persuaded to authorize the police to borrow his house key off the next-door neighbour（他答應授權警方向他隔壁鄰居借他家門的鑰匙）。這borrow something off someone的說法，較borrow something from someone隨便一點，但絕對不算錯誤。馬克．吐溫那一句，off of不必改為from，就是這個道理。
問：讀書見到以下一句：Only when the house is cleaned and the lock changed, will we move in（房子打掃乾淨以及更換鑰匙之後，我們才會搬進去）。這一句是不是應加when字，即Only when the house is cleaned and when the lock changed, will we move in？
答：原句用了省畧法，全寫如下：Only when the house is cleaned and（only when）the locked（is）changed, will we move in。假如在and之後加一when字，等於不用省畧法，也等於不要括弧裏的only、is二字，句子文法就不妥當。