從懸垂結構開始認識獨立主格結構

一、懸垂結構 Dangling Element的定義
一般在一個句子中，修飾語必須清楚地修飾句中某個詞或短語，如果它不修飾句中的任何成分，而處於懸浮狀態，這樣的修飾語即爲懸垂結構(Dangling Element)。
Climbing up the tower, the whole city came into our view.
正確的應該是：Climbing up the tower, we can see the whole city.
登上這座塔，我們能看到整個城市。
二、懸垂結構的理解
分詞短語在句子中作狀語時，其邏輯主語(亦稱隱含主語)通常應是整個句子的主語；如果不是，而且其本身也不帶自己的主語(如在獨立主格結構中)，就被認爲是一個語言失誤。這個分詞就叫做“懸垂分詞”(dangling participle)或“無依附分詞 ”(unattached participle)。例如：
(1) Getting down from the bus，my ankle was sprained．
（句子的主語是my ankle，但是獨立成分中getting down 的邏輯主語應該是I，並不是句子的主語，所以這被認爲是一個語言失誤。）
(2) Driving to Chicago that night，a sudden thought struck me．
（同理，分詞短語driving to Chicago that night沒有帶自己的主語，它的邏輯主語也不是句子的主語a sudden thought，所以也是一個語言失誤。）
三、由懸垂結構造成的錯誤
(1)懸垂分詞
誤：Being Sunday, they went for a picnic.
正：It being Sunday, they went for a picnic.
正：As it was Sunday, they went for a picnic.
(2)懸垂不定式
誤：To swim properly, a course of instruction was necessary.
正：To swim properly, one needs a course of instruction.
(3)懸垂簡式從句
誤：When a middle school student, his parents were very strict with him.
正：When he was a middle school student, his parents were very strict with him.