What are three main parts of introduction? define them

There are three parts to an introduction: the opening statement, the supporting sentences, and the introductory topic sentence. There are many ways to write an introduction, but it is necessary to include each of the three parts:

an opening statement or question that attracts the reader's attention — this is often called "the hook",

supporting sentences which link "the hook" to the thesis, and

a thesis statement that states the purpose and plan of the whole essay.

that’s the kind of bug henry was; and if we’d a had him along ’stead of our kings, he’d a fooled that town a heap worse than ourn done.”