所謂垂懸結(jié)構(gòu)（The Dangling Construction）就是一個(gè)句子成分，如分詞短語(yǔ)，不定式動(dòng)詞短語(yǔ)等，找不到被修飾的主語(yǔ)或被修飾的對(duì)象不合邏輯。垂懸結(jié)構(gòu)是種錯(cuò)誤的句法，應(yīng)該避免。
下面是三種常見(jiàn)的垂懸結(jié)構(gòu)及其改正方法：
⒈垂懸分詞或分詞短語(yǔ)，如：
① Climbing up the hill, several boars were seen.
這句子里的現(xiàn)在分詞短語(yǔ)（present participial phrase）修飾主語(yǔ)“several boars”是錯(cuò)的；改正方法有二：
（a）確定是邏輯主語(yǔ)，使句子變成“Climbing up the hill, the explorers saw several boars.”
（b）把現(xiàn)在分詞短語(yǔ)擴(kuò)大為副詞分句（也稱(chēng)狀語(yǔ)從句）：“When the explorers climbed up the hill, they saw several boars/ several boars were seen.”
⒉垂懸副詞短語(yǔ)，如：
② After putting a shrimp on the hook, the fish began to bite.
這句的副詞短語(yǔ)（adverb phrase）和主語(yǔ)“the fish”有什么邏輯關(guān)系呢？真正的邏輯主語(yǔ)應(yīng)該是“the fisherman”或“the angler”才對(duì)。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(dòng)詞短語(yǔ)，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(gè)句子的不定式動(dòng)詞短語(yǔ)（infinitive phrases）并不能修飾“practice”和“a sense of belonging”，真正的主語(yǔ)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(lèi)垂懸結(jié)構(gòu)中，第一類(lèi)發(fā)生的頻率，必須注意。但是在下列三種情況下，分詞短語(yǔ)是對(duì)的，它們并非垂懸結(jié)構(gòu)：
第一，獨(dú)立結(jié)構(gòu)（The Absolute Construction，見(jiàn)3月7日《中英合談》）中的分詞短語(yǔ)有自己的主語(yǔ)，所以不是垂懸結(jié)構(gòu)。例如：
① Such being the case, we can go home now./……it is not wrong to call it a day.
第二，當(dāng)分詞含有介詞或連詞性質(zhì)時(shí)，它不需要邏輯主語(yǔ)，所以沒(méi)有垂懸問(wèn)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(dāng)分詞短語(yǔ)是用來(lái)表示說(shuō)話者的態(tài)度或意見(jiàn)時(shí)，也不需要邏輯主語(yǔ)，因此也不存在著垂懸問(wèn)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.
下面是三種常見(jiàn)的垂懸結(jié)構(gòu)及其改正方法：
⒈垂懸分詞或分詞短語(yǔ)，如：
① Climbing up the hill, several boars were seen.
這句子里的現(xiàn)在分詞短語(yǔ)（present participial phrase）修飾主語(yǔ)“several boars”是錯(cuò)的；改正方法有二：
（a）確定是邏輯主語(yǔ)，使句子變成“Climbing up the hill, the explorers saw several boars.”
（b）把現(xiàn)在分詞短語(yǔ)擴(kuò)大為副詞分句（也稱(chēng)狀語(yǔ)從句）：“When the explorers climbed up the hill, they saw several boars/ several boars were seen.”
⒉垂懸副詞短語(yǔ)，如：
② After putting a shrimp on the hook, the fish began to bite.
這句的副詞短語(yǔ)（adverb phrase）和主語(yǔ)“the fish”有什么邏輯關(guān)系呢？真正的邏輯主語(yǔ)應(yīng)該是“the fisherman”或“the angler”才對(duì)。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(dòng)詞短語(yǔ)，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(gè)句子的不定式動(dòng)詞短語(yǔ)（infinitive phrases）并不能修飾“practice”和“a sense of belonging”，真正的主語(yǔ)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(lèi)垂懸結(jié)構(gòu)中，第一類(lèi)發(fā)生的頻率，必須注意。但是在下列三種情況下，分詞短語(yǔ)是對(duì)的，它們并非垂懸結(jié)構(gòu)：
第一，獨(dú)立結(jié)構(gòu)（The Absolute Construction，見(jiàn)3月7日《中英合談》）中的分詞短語(yǔ)有自己的主語(yǔ)，所以不是垂懸結(jié)構(gòu)。例如：
① Such being the case, we can go home now./……it is not wrong to call it a day.
第二，當(dāng)分詞含有介詞或連詞性質(zhì)時(shí)，它不需要邏輯主語(yǔ)，所以沒(méi)有垂懸問(wèn)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(dāng)分詞短語(yǔ)是用來(lái)表示說(shuō)話者的態(tài)度或意見(jiàn)時(shí)，也不需要邏輯主語(yǔ)，因此也不存在著垂懸問(wèn)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.