10大標點符號常見錯誤(4):不定詞前面有comma嗎?

我曾經寫過一篇講介詞短語.我說介詞短語又可做形容詞,又可作副詞,很百搭. 我唸起,其實不定詞(To-infinitive)也有這個特徵,它可作形容詞修飾名詞,如:

The best way to prevent cancer is healthy diet. 

句中的to prevent cancer便是修飾way的. 

又可作副詞,修飾動詞:

Mary is taking a Semantics course this year to understand the relationship between words. 

句中的to understand the relationship between words是修飾is taking,解釋為何Mary要take a Semantics course.

不定詞之所以叫不定詞,就係因為To+infinitive的詞性不定,除了形容詞及副詞,它比介詞短語更多功能,可作名詞:

I hope to win the lottery. 

句中的to win the lottery是hope的受詞, 又或:

To succeed is my goal. 

句中的To succeed主詞也是名詞.

不過今篇主題係講標點符號.

因為不定詞可以係唔同位置出現,包括句子頭、句子中、和句子尾.例如:

To avoid being punished by the teacher, she submits homework on time. (不定詞短語修飾動詞submit)

The movie, to be honest, is boring. (不定詞短語to be honest是sentence adverb,或稱disjunct,修飾整句句子)

Vanessa and her friends went to the shopping mall, to meet her boyfriend. (不定詞短語to meet her boyfriend修飾動詞went)

請大家看清楚以上三句,其中一句月標點符號問題.是哪一句?

就是第三句了!原來,若不定詞放在句子最後,是不用加comma的.因此,句子應為:

Vanessa and her friends went to the shopping mall to meet her boyfriend.

 (比較，介詞短語卻可以跟comma後面, 例如:

As a modern city, it is only right that the people of Hong Kong should be able to enjoy a better environment, with clean streets and markets as well as a beautiful countryside.）