在连串单词，短语和分句后使用逗号。
用逗号将长的介绍性的从属分句和短语(四个或更多单词)分开。
Set off long introductory dependent clauses and phrases (four or more words) with a comma.
这些从属分句和短语不包含句子主语和谓语，不能单独组成句子。
These clauses and phrases do not include the subject and verb of the sentence, and they cannot stand alone as complete sentences.
本文主要从短语和句子层面上，探讨了以下几点：中心名词与形容词性分句结构关系的特征；
From the phrasal and sentential level, following points are discussed in this thesis: the characteristic of structural relationships between the head noun and its adjective clause;
本文主要从短语和句子层面上，探讨了以下几点：中心名词与形容词性分句结构关系的特征；
From the phrasal and sentential level, following points are discussed in this thesis: the characteristic of structural relationships between the head noun and its adjective clause;
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