教师解析：

I.What is syntax?

 The term syntax is from the ancient Greek word syntaxes, which literally means “arrangement” or “setting out together”.

 Traditionally, it refers to the branch of grammar dealing with the ways in which words, with or without appropriate inflections, are arranged to show connections of meaning within the sentence.

 Syntax is a branch of linguistics that analyzes the structure of sentences.

II. What is a sentence?

 Syntax is the analysis of sentence structure. A sentence is a sequence of words arranged in a certain order in accordance with grammatical rules.

 A sequence can be either well-formed or ill-formed. Native speakers of a language know intuitively what strings of words are grammatical and what are ungrammatical.