英語講義【39】垂懸結構
所謂垂懸結構（The Dangling Construction）就是一個句子成分，如分詞短語，不定式動詞短語等，找不到被修飾的主語或被修飾的對象不合邏輯。垂懸結構是種錯誤的句法，應該避免。
下面是三種常見的垂懸結構及其改正方法：
⒈垂懸分詞或分詞短語，如：
① Climbing up the hill, several boars were seen.
這句子里的現在分詞短語（present participial phrase）修飾主語several boars是錯的；改正方法有二：
（a）確定是邏輯主語，使句子變成Climbing up the hill, the explorers saw several boars.
（b）把現在分詞短語擴大為副詞分句（也稱狀語從句）：When the explorers climbed up the hill, they saw several boars/ several boars were seen.
⒉垂懸副詞短語，如：
② After putting a shrimp on the hook, the fish began to bite.
這句的副詞短語（adverb phrase）和主語the fish有什么邏輯關系呢？真正的邏輯主語應該是the fisherman或the angler才對。改正方法和例①同：
（a） After putting a shrimp on the hook, the fisherman found that the fish began to bite.
（b） After the fisherman had put a shrimp on the hook, the fish began to bite.
⒊垂懸不定式動詞短語，如：
③ To write well, a lot of practice is needed.
④ To be a loyal employee, a sense of belonging is a must.
這兩個句子的不定式動詞短語（infinitive phrases）并不能修飾practice和a sense of belonging，真正的主語必須是 人，如：
（a） To write well, one needs a lot of practice/a person has to practise a lot.
（b） To be a loyal employee, he or she must have a sense of belonging.
上述三類垂懸結構中，第一類發生的頻率最高，必須注意。但是在下列三種情況下，分詞短語是對的，它們并非垂懸結構：
第一，獨立結構（The Absolute Construction，見3月7日《中英合談》）中的分詞短語有自己的主語，所以不是垂懸結構。例如：
① Such being the case, we can go home now./it is not wrong to call it a day.
第二，當分詞含有介詞或連詞性質時，它不需要邏輯主語，所以沒有垂懸問題存在。例如：
② Owing to a lack of funds, the project has to be discontinued.
③ Provided that there is sufficient time, everyone can do the job better.
第三，當分詞短語是用來表示說話者的態度或意見時，也不需要邏輯主語，因此也不存在著垂懸問題。例如：
④ Judging from his facial look, the news must have been terrible.
⑤ Taken as a whole, there is nothing wrong with the logic behind that idea.
所謂垂懸結構（The Dangling Construction）就是一個句子成分，如分詞短語，不定式動詞短語等，找不到被修飾的主語或被修飾的對象不合邏輯。垂懸結構是種錯誤的句法，應該避免。
下面是三種常見的垂懸結構及其改正方法：
⒈垂懸分詞或分詞短語，如：
① Climbing up the hill, several boars were seen.
這句子里的現在分詞短語（present participial phrase）修飾主語several boars是錯的；改正方法有二：
（a）確定是邏輯主語，使句子變成Climbing up the hill, the explorers saw several boars.
（b）把現在分詞短語擴大為副詞分句（也稱狀語從句）：When the explorers climbed up the hill, they saw several boars/ several boars were seen.
⒉垂懸副詞短語，如：
② After putting a shrimp on the hook, the fish began to bite.
這句的副詞短語（adverb phrase）和主語the fish有什么邏輯關系呢？真正的邏輯主語應該是the fisherman或the angler才對。改正方法和例①同：
（a） After putting a shrimp on the hook, the fisherman found that the fish began to bite.
（b） After the fisherman had put a shrimp on the hook, the fish began to bite.
⒊垂懸不定式動詞短語，如：
③ To write well, a lot of practice is needed.
④ To be a loyal employee, a sense of belonging is a must.
這兩個句子的不定式動詞短語（infinitive phrases）并不能修飾practice和a sense of belonging，真正的主語必須是 人，如：
（a） To write well, one needs a lot of practice/a person has to practise a lot.
（b） To be a loyal employee, he or she must have a sense of belonging.
上述三類垂懸結構中，第一類發生的頻率最高，必須注意。但是在下列三種情況下，分詞短語是對的，它們并非垂懸結構：
第一，獨立結構（The Absolute Construction，見3月7日《中英合談》）中的分詞短語有自己的主語，所以不是垂懸結構。例如：
① Such being the case, we can go home now./it is not wrong to call it a day.
第二，當分詞含有介詞或連詞性質時，它不需要邏輯主語，所以沒有垂懸問題存在。例如：
② Owing to a lack of funds, the project has to be discontinued.
③ Provided that there is sufficient time, everyone can do the job better.
第三，當分詞短語是用來表示說話者的態度或意見時，也不需要邏輯主語，因此也不存在著垂懸問題。例如：
④ Judging from his facial look, the news must have been terrible.
⑤ Taken as a whole, there is nothing wrong with the logic behind that idea.
