Topic

（1）话题

（2）(Topic Sentence)话题句

(1) A term used in semantics and grammar as part of an alternative binary characterization of sentence structure to that traditionally found in the subject / predicate distinction; the opposite term is comment. The topic of a sentence is the entity (person, thing, etc.) about which something is said, whereas the further statement made about this entity is the comment. The usefulness of the distinction is that it enables general statements to be made about the relationships between sentences which the subject / predicate distinction (along with other contrasts of this type) obscures. The topic often coincides with the subject of a sentence, but it need not , and, even when it is a subject, it need not come first in a sentence. It is sometimes referred to as the ‘psychological subject’. Topicalization takes place when a constituent is moved to the front of a sentence, so that it functions as topic.

(2) The phrase topic sentence is used in traditional studies of the structure of paragraphs, to refer to the sentence which introduces the paragraph’s theme.

（1）语义学和语法对句子结构的二分描写用话题/评述来取代传统的主语/谓语二分法。句子的话题是对其作出说明的那个实体（人、物等），而对这个实体的进一步说明则是评述。这种区分的好处是能对句子之间的一些关系作出概括的说明，而这些关系被主语/谓语的区分（以及其他类似的对立）所掩盖。话题常与句子的主语重合，但不总是重合，而且话题即便是主语也不一定位于句首。话题有时称作“心理主语”。话题化是指一个组构成分移到句首位置充当话题。

（2）这个术语在对段落结构的传统研究中指引入段落主题的那个句子。