The beauty of sentences lies in clarity, the choice of words and how effectively the thought flows. If words are pearls then a great sentence can be described as a beautiful pearl necklace. Sentences convey more than meaning; they convey style. Now, when writing sentences, it must be understood that it consists of two important constituents-structure and purpose.
Sentence Types:
Sentences are classified in two ways-structure and purpose.
- By Structure
 
This is a traditional form of classifying sentences wherein, the sentences are classed depending on the number and types of finite clauses.
- Simple Sentence
 
In this type of sentence, there is only one independent clause and no dependent clause. The sentence contains a subject and a verb and expresses a complete thought. Simple sentences can also contain compound subjects and/or verbs but it doesn't contain any conjunction.
- Some students (subject) like (verb) to study in the mornings.
 - Juan (subject) plays (verb) football every afternoon.
 - Alicia (subject) goes (verb) to the library and studies (verb) every day.
 
- Compound Sentence
 
In this type of sentence, there are multiple independent clauses and no dependent clause. All the clauses are joined together by coordinating conjunctions and/or punctuations. Here, the relationship between the two independent clauses can be changed by the proper use of coordinating conjunctions.
- I (subject) tried (verb) to speak Spanish, and my friend (subject) tried (verb) to speak English.
 - Alejandro (subject) played (verb) football, so Maria (subject) went (verb) shopping.
 - Alejandro (subject) played (verb) football, for Maria (subject) went (verb) shopping.
 
- Complex Sentence
 
This type of sentence consists of at least one independent clause and one dependent clause. One characteristic of complex sentence is that it has a relative pronoun like 'that', 'who' or 'which' or a subordinator like 'because', 'since', 'when', 'although' or 'after'. If the complex sentence begins with a subordinator then a comma is placed after the dependent clause. When the sentence begins with an independent clause and the subordinators are in the middle, then there is no need to place a comma after the dependent clause.
- When (subordinator) he (subject) handed (verb) in his homework, he (subject) forgot (verb) to give the teacher the last page.
 - The teacher (subject) returned (verb) the homework after (subordinator) she (subject) noticed (verb) the error.
 - The students (subject) are studying (verb) because (subordinator) they (subject) have (verb) a test tomorrow.
 - After (subordinator) they (subject) finished (verb) studying, Juan (subject) and Maria (subject) went (verb) to the movies.
 - Juan (subject) and Maria (subject) went (verb) to the movies after (subordinator) they (subject) finished (verb) studying.
 
- Compound-Complex Sentence
 
This type of sentence consists of multiple independent clauses and at least one dependent clause. The clauses are connected by both conjunctions and subordinators.
- The woman (subject), who (subordinate) my mom (subject) talked to, sells (verb) cosmetics.
 - The book (subject) that (subordinate) Jonathan (subject) read is (verb) on the shelf.
 - The house (subject) which (subordinate) Abraham Lincoln (subject) was born in is (verb) still standing.
 - The town (subject) where (subordinate) I (subject) grew up is (verb) in the United States.
 
- By Purpose
 
Sentences are also classified based on their purpose.
- Declarative Sentence
 
This type of sentence, also known as a declaration, is generally used to make a statement. This sentence "declares" a fact or opinion and can be either positive or negative. Declarative sentences always end with a period.
- I am happy.
 - That bird is flying.
 - I deposited my money in the bank.
 
- Interrogative Sentence
 
This type of sentence asks a question or request information. However, rhetorical questions do not fall into the category of interrogative sentences. Interrogative sentence always ends with a question mark.
- When did you turn the lights off?
 - Do you know how to ride a bike?
 - Please tell me the real reason why you came here?
 
- Exclamatory Sentence
 
This type of sentence expresses an exclamation; it is a form of statement expressing emotion or excitement. Exclamatory sentences always end with an exclamation mark to emphasize a statement.
- “Good night!” she said.
 - Wow! What a dream.
 - What a beautiful sunrise!
 
- Imperative Sentence
 
This type of sentence is in the form of a command. This is a sentence which tells someone to do something. Imperative sentence, when framed strongly enough, can also be exclamatory. Imperative sentence can also be used to make a request and end with a period.
- Please give me that book.
 - Finish all your chores before you go out.
 - I want to eat pizza tonight.
 
- Conditional Sentence
 
In this type of sentence, a condition is implied and what one would do if the conditions were met. It generally depends on the use of 'if'.
- If I had 100 bucks, I would go for an ice-cream.
 - I could have done this for you only if I had the time.
 
