A sentence is a group of words that makes complete sense. A complete sentence has three characteristics:
1. It begins with a capital letter.
2. In addition, it includes an end mark—either a period [.], question mark [?], or exclamation point [!].
3. Most important, the complete sentence must contain at least one main clause. A main clause contains an independent subject and verb(predicare) and expresses a complete thought.
Tom and Harry went to the market.
Where did Tom and Harry go?
What a fascinating things in the market!