Basic English Sentence Structures

English has three main sentence types: Declarative Sentences are used to form statements.
Examples: "Mary is here.", "My name is Mary."

Interrogative Sentences are used to ask questions.
Examples: "Where is Mary?", "What is your name?"

Imperative Sentences are used for commands.
Examples: "Come here.", "Tell me your name."
It is not polite to use imperative sentences without the word "Please". It is better to say "Please, come here." than just "Come here." The simplest English sentences are imperative sentences with a single verb (Example: "Help!").

Sentences may be simple or compound. Compound sentences consist of two or more simple sentences joined by conjunctions.
Examples:
"Come here and sit down.",
"My name is Mary and I live in New York.",
"What is your name and where do you live?",
"Either John will go to New York or Mary will come here."

It is not correct to combine different sentence types in a compound sentence. Wrong: "Mary lives in New York and come here."

<English Sentence> =
       <Simple Sentence> |
       <Compound Sentence>

<Simple Sentence> =
       <Declarative Sentence> |
       <Interrogative Sentence> |
       <Imperative Sentence>

<Compound Sentence> =
       <Simple Sentence> <conjunction> <Simple Sentence> |
       "Either" <Simple Sentence> "or" <Simple Sentence>