Syntax and Punctuation

Syntax refers to sentence structure: the group(s) of words put together to form a sentence and how they're arranged.  Syntax involves such questions as sentence length and the way a sentence is punctuated.  To understand syntax we have to look once more at how words are grouped together.

Sentence Fragment
Comma Splice
Conjunctions and Conjunctive Adverbs


A phrase is a group of words that may include the subject of the sentence or its verb but not both; it may also be based on some other kind of word, like a preposition. 

A noun or verb phrase usually includes a modifier of some kind. 

     the brown dog
     runs quickly

A prepositional phrase may itself be a modifier; for example, the phrase may act as an adverb, telling us more about the verb:

     I walked down the street. (the prepositional phrase "down the street" modifies "walked")


A clause is a group of words containing both a subject and its verb.  There are two kinds, and it is very important to remember the distinction:

A main (or independent) clause expresses a complete thought:

     the student will pass the exam.

A subordinate (or dependent) clause expresses a thought that depends in some way on another one.  It may express when, if, or why something else happens:

     because she studied
     if she studies
     when she takes it

A subordinate clause needs something else--that is, a main clause--in order for it to make sense.  That's why we say it's subordinate or dependent.


Most people define a sentence as a group of words that expresses a complete thought.  A main clause expresses a complete thought.  Therefore, every sentence must contain at least one main clause.  It may contain more than one, and it may contain any number of subordinate clauses and phrases, but it has to have at least one main clause.
A sentence begins with a capital letter and ends with a period, exclamation mark, or question mark. 

Sentence Fragment (SF or frag)
Sometimes, a student will write a word, phrase, or subordinate clause with a capital letter at the beginning and a period at the end.  Because this "sentence" does not contain a main clause, it is not a sentence but a sentence fragment.  The sentence fragment is one of the worst grammatical errors.

     To the store.
     Because I needed bread.
     When I go to the store.


To join words, phrases, and clauses together we use conjunctions.  As the term implies, a conjunction is a word that joins other words.  When it comes to joining clauses together, there are two kinds:

Coordinating conjunction: joins two main clauses:

     and, but, or

Subordinating conjunction: subordinates one of the clauses to the other, turning it into a subordinate clause:

     because, when, if, although, whereas
Consider the following examples.  In each of the first group, the main clauses remain independent; the writer joins them together with a coordinating conjunction to form a longer sentence:

     I went to the store [main clause] and I bought some bread [main clause].
     I went to the store [main clause] but I forgot to buy bread [main clause].
     I will go to the store [main clause] or I will go to the bank [main clause].

Now, the writer takes one clause and subordinates it to the other:

     I went to the store [main clause] because I needed bread [subordinate clause].
     I will go to the store [main clause] when I have finished at the bank [subordinate clause].
     I did not get any bread [main clause], although I needed to buy some [subordinate clause].
     If I go to the store [subordinate clause] I will buy some bread [main clause].

Note that it does not matter whether the subordinate clause comes before or after the main clause, as long as the main clause is there:

     Because I needed bread [subordinate clause] I went to the store [main clause].

Punctuation with conjunctions:

You do not need to add punctuation if the clauses are short.  If they're long, however, and especially if you use "but," it is a good idea to add a comma before the conjunction:

     I went to the store during my lunch hour at noon, and I bought a loaf of bread.
     I did not want to go to the store on a busy Saturday afternoon, but I needed to buy bread.

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Punctuation is one of the most complex and difficult areas of grammar.  However, there are certain rules and tricks that can make things easier.  Keep in mind that the rules of punctuation are designed to make writing logical and easy to understand.


The mark that students (and others) have a great deal of trouble with is the semi-colon.  The semi-colon's main purpose is to connect two ideas that are closely related to each other, and in fact the second one usually offers some sort of explanation of the first.  In grammatical terms, here is the rule:
Use a semi-colon only between two main clauses:

     I had to go to the store; I needed to buy bread.
     This is not the first time he got into trouble; he had problems last year, too.

Here's a simple trick: since a semi-colon comes between two main clauses, each of which could form a sentence all on its own, you should be able to replace a semi-colon with a period.  If you can't substitute a period for your semi-colon, you're using it incorrectly and should find another punctuation mark.

(There is one other use of semi-colons, but it's rare and you may never have need of it.  The semi-colon is used to separate items in a list with internal punctuation:

     He invited Jan, a doctor; Anne, a lawyer; and Bill, a teacher.

This way, the reader knows that "a doctor" refers to Jan, for example, and not to a different person altogether.)


Use a colon to introduce a list, even if it is a list of only one item.  The colon is especially useful after a main clause that includes a number or a classification.  What follows the colon can be a word, phrase, or clause:

     The book deals with two important issues: health care and the environment.
     I returned to school for one main reason: interest. (word)
                                                                   love of learning. (phrase)
                                                                   because I love to learn. (subordinate clause)
                                                                   I love to learn. (main clause)

Use a colon to introduce a quotation if your words don't flow smoothly into the quotation:

     Kent says that we cannot afford to wait: "We have to act now to save the planet."
     (But: Kent says that we "have to act now to save the planet.")


The most used and abused punctuation mark is the comma
Use a comma before a conjunction (see above).
Use a comma to separate the items in a list.  If you use it in a list, add one before the final item in the list:

     lions, tigers, and bears

Use commas to set off a parenthetical word or statement
Sometimes, you don't need or want to set it off; it depends on whether what you've added is essential to understanding the sentence.  If you use a clause that's necessary, it's called a "restrictive clause" and you should not use any commas.  If the clause is unnecessary, but just provides extra information, use commas to set it off.  The point is that in such cases use two commas or none:

     The team that gets the most points wins the game. ("that gets the most points" is a restrictive clause; it
          provides essential information)
     The team, which won the game last week, was given a parade today. ("which won the game last week"
          is a non-restrictive clause)
     Diane, the shortstop, will bat second.
     Martin returned and, exhausted, went straight to bed.

Use a comma after an initial adverb: that is, one that comes at the beginning of a clause:

     Unfortunately, I forgot to buy bread.   

Comma Splice (CS)

There is one thing that you cannot do with a comma: you must not use a comma alone to join two main clauses.  This error is known as a comma splice and is one of the worst grammatical faults:

     I went to the store to buy bread, I found that I did not have enough money.
     I went to the store to buy bread, unfortunately, I did not have enough money.

Revise the sentence by adding a conjunction or using a semi-colon:

     I went to the store to buy bread, but I found that I did not have enough money.
     I went to the store to buy bread; unfortunately, I did not have enough money.

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Conjunctions and Conjunctive Adverbs

There is a group of words known as conjunctive adverbs that cause a great deal of confusion.  The reason is that they seem to be conjunctions but they aren't.  Most adverbs end in "-ly" but conjunctive adverbs do not and so are easily mistaken for conjunctions.  "However," for example, seems like a fancier way of saying "but," while "moreover" and "furthermore" seem like fancier ways of saying "and."  It is important to remember that these are two different kinds of words and you shouldn't use conjunctive adverbs as conjunctions.
The most commonly used conjunctive adverbs are:

     furthermore, however, moreover, nevertheless, therefore, thus (sometimes)

The problem arises when the conjunctive adverb appears at the beginning of a clause.  It could appear anywhere, just like any other adverb, but when it appears at the beginning it seems to be acting as a conjunction.  Let's compare a couple of adverbs--first, we'll look at one that ends in "-ly" and thus looks like an adverb:

     Unfortunately, I did not have enough money.
     I did not, unfortunately, have enough money.
     I did not have enough money, unfortunately.

Now, let's substitute a conjunctive adverb:

     However, I did not have enough money.
     I did not, however, have enough money.
     I did not have enough money, however.

Because "however" seems to be like "but"--but with more syllables and therefore apparently more elegant and formal--students often use it as a conjunction:

     I went to the store to buy bread, however I did not have enough money.

The problem is that "however," not being a conjunction, does not join two main clauses together; instead, it is part of the second main clause.  As a result, two main clauses are being joined together by a comma alone, in the absence of a conjunction, and so you get a comma splice:

                 FIRST MAIN CLAUSE                                     SECOND MAIN CLAUSE
     [I went to the store to buy bread], [however I did not have enough money]

Note that "however," like other initial adverbs, must be followed by a comma (see above).  To join together two main clauses, use a semi-colon:

     I went to the store to buy bread; however, I did not have enough money.

Most commonly, students incorrectly use conjunctive adverbs in place of conjunctions.  Sometimes, however, they use conjunctions (especially subordinating conjunctions) where they should use conjunctive adverbs:

     Although, I found that I did not need to buy it after all.

The word should be "However" or "Nevertheless"--or even "Unfortunately"...

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