A sentence is a group of words that you use to communicate your ideas. Every sentence is formed from one or more clauses and expresses a thought, which makes a focal impression on the readers’ mind. Does a person wish to show an outburst of emotion? Use an exclamatory sentence. Does he desire to show a smooth flow of feeling? Use a long, periodic sentence. In an ordinary way a sentence is capable of expressing a complete thought, whether a statement, command, question, or exclamation.
Clauses
Clauses are the building blocks of sentences. A clause is a group of words that contains (at least) a subject and a verb.
There are two kinds of clauses: independent and dependent.
1. Independent clauses
An independent clause contains a subject and a verb and expresses a complete thought. It can stand alone as a sentence by itself. An independent clause is formed with
subject + verb (+ complement)
Students normally spend four years in college.
Many international students experience culture shock.
2. Dependent clauses
A dependent clause begins with a subordinator such as when, while, if, that, or who. It does not express a complete thought and cannot stand alone as a sentence by itself. A dependent clause is formed with
subordinator +subject + verb (+ complement)
…although students normally spend four years in college…
… when they came to the United States…
3. Clause connectors
Three groups of words are used to connect clauses in order to form different kinds of sentences.
Group 1 — subordinators (subordinating conjunctions): after, although, as, as if, as soon as, because, before, even though, how, if, since, so that, that, though, unless, until, what, whether, when, whenever, where, wherever, which, while, who, whom, whose, …
Group 2 — seven coordinators (coordinating conjunctions): for, and, nor, but, or, yet, so (You can remember them by the phrase FAN BOYS.)
Group 3 — conjunctive adverbs: accordingly, furthermore, in contrast, meanwhile, on the other hand, besides, hence, indeed, moreover, otherwise, consequently, however, instead, nevertheless, therefore, for example, in addition, likewise, nonetheless, thus, …
Kinds of Sentences
According to structure, there are basically four kinds of sentences in English: simple, compound, complex, and compound-complex, which is determined by the kind of clauses used to form it.
1. Simple sentences
A simple sentence is one independent clause.
I enjoy playing tennis with my friends every weekend.
I enjoy playing tennis and look forward to it every weekend.
My friends and I play tennis and go bowling every weekend.
Notice that the second sentence has two verbs, enjoy and look forward to. This is called a compound verb. Because there is only one clause, this is a simple sentence. The third sentence has a compound subject and a compound verb, but it is still a simple sentence because it has only one clause.
2. Compound sentences
A compound sentence is joined together by two or more independent clauses. There are three ways to join the clauses:
Let’s study each type of compound sentence in more details.
Compound sentences with coordinators
A compound sentence can be formed as follows:
Independent clause, + coordinator + independent clause.
Notice that there is a comma after the first independent clause.
Women live longer than men, for they take better care of their health.
For
The second clause gives the reason for the first clause.
Women follow more healthful diets, and they go to doctors more often.
And
The two clauses express equal, similar ideas.
Women don’t smoke as much as men do, nor do they drink as much alcohol.
Nor
Nor means “and not”. It joins two negative independent clauses. Notice that the question word order is used after nor.
Men may exercise harder, but they may not exercise as regularly as women do.
But
The two clauses express equal, contrasting ideas.
Both men and women should limit the amount of fat in their diets, or they risk getting heart disease.
Or
The two clauses express alternative possibilities.
Women used to be known as the “weaker sex”, yet in some ways, they are stronger than men.
Yet
The second clause is a surprising or unexpected contrast to the first clause.
Men are less cautious than women, so more men die in accidents.
So
The second clause is the result of the first clause.
Independent clause; + conjunctive adverb, + independent clause.
Notice the punctuation: a semicolon follows the first independent clause, and a comma follows the conjunctive adverb. Also, just like the FAN BOYS coordinators, conjunctive adverbs express relationships between the clauses. The following chart shows the coordinators and conjunctive adverbs that express similar meanings.
3) Compound sentences with semicolons
A compound sentence can also be formed with a semicolon alone:
Independent clause; + independent clause.
Call me tomorrow; I will give you my answer then.
This kind of compound sentence is possible only when the two independent clauses are closely related in meaning. If they aren’t closely related, they should be written as two simple sentences, each ending with a period.
3. Complex sentences
A complex sentence contains one independent clause and one (or more) dependent clause(s). In a complex sentence, one idea is generally more important than the other one. The more important idea is placed in the independent clause, and the less important idea is placed in the dependent clause.
There are three kinds of dependent clauses: adverb, adjective, and noun. The following chart presents an overview of them.
DEPENDENT CLAUSES
Adverb Clauses
A dependent adverb clause begins with an adverbial subordinator such as when, while, because, although, if, so that, etc.
Although women could own property, they could not vote until 1920.
In the United States, women could not vote until 1920 although they could own property.
Notice that there are two possible positions for an adverb clause: before or after the independent clause. If it comes before the independent clause, it is followed by a comma (sentence 1). If it comes after the independent clause, no comma is needed (sentence 2).
Adjective Clauses
A dependent adjective (relative) clause begins with a relative pronoun such as who, whom, which, whose, or that, or with a relative adverb such as where or when. An adjective clause functions as an adjective; that is, it modifies a noun or pronoun.
Position of relative clauses:
Place a relative clause after its antecedent and as close to it as possible to avoid confusion.
Confusing: He left the gift in his friend’s car that he had just bought.
(It is not clear whether the relative clause modifies car or gift.)
Revised: He left the gift that he had just bought in his friend’s car.
(The relative clause clearly modifies gift.)
Occasionally, a prepositional phrase comes between the antecedent and the relative clause.
Try writing a sentence of your own that contains a relative clause.
Punctuation of relative clauses:
Relative clauses are either restrictive or nonrestrictive. A restrictive clause is necessary because it identifies its antecedent for the reader. Do not use commas with restrictive clauses: He won the prize for research that might lead to a cure for AIDS.
A nonrestrictive clause is not necessary to identify its antecedent; it merely gives the reader some extra information. Because it can be omitted without the loss of meaning, it should be separated from the rest of the sentence with commas: Professor Jones, who teaches my biology class, won a Nobel Prize two years ago.
Noun Clauses
A dependent noun clause functions as a noun and begins with a wh-question word, that, whether, or sometimes if. A dependent clause can be either a subject or an object. No commas are necessary.
That there is a hole in the ozone layer of the earth’s atmosphere is well known. (subject)
Scientists believe that excess chlorofluorocarbons in the atmosphere are responsible for creating it. (object)
4. Compound-complex sentences
A compound-complex sentence is a combination of two or more independent clauses and one (or more) dependent clause(s). Many combinations are possible, and their punctuation requires careful attention.
Let’s study the following sentences:
I wanted to travel after I graduated from college; however, I had to go to work immediately.
After I graduated from college, I wanted to travel, but I had to go to work immediately.
I wanted to travel after I graduated from college, but I had to go to work immediately because I had to support my family.
I couldn’t decide where I should work or what I should do, so I did nothing.
Punctuate the compound part of a compound-complex sentence like a compound sentence; that is, use a semicolon/ comma combination (sentence 1), or put a comma before a coordinator joining two clauses (sentence 2, 3, and 4).
Punctuate the complex part like a complex sentence. With adverb clauses, put a comma after a dependent adverb clause (sentence 2) but not before them (sentence 3). With noun clauses, use no commas (sentence 4).
Good writing requires a mixture of all four kinds of sentences: simple, compound, complex, and compound-complex. A composition with only short, simple sentences is boring and ineffective, so is writing that uses too many compound sentences. Writing with complex sentences and participle phrases, structures that use subordination, is generally considered a more mature, interesting and effective style.
