如果對He lives in Beijing . 中的畫線部分提問,應為:Where does he live ? 這里的where是疑問副詞,作狀語,替代原句中的地點狀語in Beijing。不可說成:Where does he live in ? 因為in是介詞,必須帶賓語才行,而副詞where這里是作狀語的,不能作賓語。但如果特殊疑問詞是代詞,這種結構又必須用in。
What city does he live in ?
Which city does he live in ?
這里的what city和which city都是名詞詞組,作in的賓語,in不可省,因為live表示“居住”是不及物動詞,不能跟賓語,如不能說live a city, live Beijing。
比較
Which room was he born in ? (正) 他出生在哪個房間?
Which room was he born ? (誤)