How to use a colon

For some reason, colons have a tendency to make people nervous. There’s really no reason for concern, though, because there are only three things you need know in order to use them flawlessly.


Colons can be used in two situations:


1) Before a list

New England consists of six states: Maine, Vermont, New Hampshire, Massachusetts, Rhode Island, and Connecticut.


2) Before an explanation

Correct: I spoke to my supervisor, and this is what she said: I should come in early tomorrow morning in order to make up for the shift that I missed last night. 

The first half of the sentence sets up the information after the colon, which explains what the supervisor said. 

 

Let’s look at a slightly more challenging example.

Correct: The Greek goddess Athena was a complex figure: she was a patron of the arts and music, but she also was a warrior who was typically depicted as wearing armor and carrying a shield.

Again, the second half of the sentence expands on the first — it explains why Athena was a complex figure. 

 

Now, there is an additional requirement:

The sentence before a colon must be able to stand on its own as a complete thought. 

For instance, in the second example above, the statement The Greek goddess Athena was a complex figure is both a grammatically complete sentence and a statement that makes sense on its own. 

 

In contrast, we cannot say this: 

Incorrect: The Greek goddess Athena was: a complex figure. 

Even though The Greek goddess Athena was is technically a complete sentence because it contains a subject (The Greek goddess Athena) and a verb (was), it does not make sense as an independent thought. 

 

One more example. 

Incorrect: In recent years, forest fires have become: an increasing threat in the United States and abroad.

Because In recent years, forest fires have become does not make sense as an independent statement, it should not come before a colon.

Correct: In recent years, forest fires have become an increasing threat: they burn earlier and later in the year, both in the United States and abroad. 

Because In recent years, forest fires have become an increasing threat does make sense on its own, it can come before a colon.

 

No That = No Comma

Questions that look like the following appear on the English portion of virtually every ACT:

What do you get when you cross a chicken with an apple? A daffodil with rice? A flounder with a tomato? These aren’t jokes, waiting for a punch line.

A. NO CHANGE
B. jokes waiting
C. jokes, waiting
D. jokes, waiting,

Although this appears to be a question about commas, it’s actually about something else entirely: relative clauses. Now, the term “relative clause” is one that I avoid whenever possible; it tends to make people a little bit nervous. It also sounds kind of icky and grammatical, the sort of thing that’s so absurdly complicated that it makes you want to throw up your hands in utter defeat before you’ve even started to try to understand what it is.

Here’s the thing, though: relative clauses aren’t actually that hard. And in order to be certain about these questions — which can be among the trickiest English questions on the ACT — it really helps to understand the basic grammar behind them.

Relative pronouns are words like which, who(se), and that. They are frequently used to connect two sentences that would sound stiff and unnecessarily repetitive when written separately.

Who

Without relative pronoun: I saw a man. The man was eating a hamburger.

With relative pronoun: I saw a man who was eating a hamburger.

That

Without relative pronoun: This is the book. I read the book yesterday.

With relative pronoun: This is the book that I read yesterday.

It is also possible to join the sentences and create a relative clause without using a relative pronoun. For example:

Correct: I saw a man who was eating a hamburger.

OR

Correct: This is the book that I read yesterday.

When you get rid of the relative pronoun, however, you do not ever need to replace it with a comma — but this is exactly what the ACT does. And in the vast majority of instances, the pronoun in question will be that:

Correct: This is the book that I read yesterday

Correct: This is the book I read yesterday

Incorrect: This is the book, I read yesterday.

Which brings us back to the original question. The underlined portion of the sentence is in fact a relative clause. It could have also been written this way:

These aren’t jokes that are waiting for a punch line.

But since the relative pronoun that doesn’t appear in the sentence, no comma is necessary. The answer is therefore B (“These aren’t jokes waiting for a punchline.”)

Recognizing these questions can take a little bit of thought — they’re easy to overlook if you’re not expecting them to be there. But since there’s at least one on pretty much every single test, learning to recognize them can get you a guaranteed point or two.

No comma before or after a preposition

One of the most common grammatical errors on the ACT English Test and, to a slightly lesser extent, the SAT Writing Test is the use of a comma before or after a preposition (a “time” or “location” word).

Common prepositions:

Of, To, For, From, In, On, By, Between, About, With, Around, Across, Through, Over, Under

This construction is virtually always incorrect, and any answer that contains it should automatically be eliminated. Note that even if the original version in the passage doesn’t contain it, one or more of the other answers might include it.

Incorrect: The gentle rustling of leaves in the breeze, the crunch of twigs underfoot, and the eclectic mix of birdsong are the sounds one typically expects to hear while walking, through the forest.

Incorrect: The gentle rustling of leaves in the breeze, the crunch of twigs underfoot, and the eclectic mix of birdsong are the sounds one typically expects to hear while walking through, the forest.

Correct: The gentle rustling of leaves in the breeze, the crunch of twigs underfoot, and the eclectic mix of birdsong are the sounds one typically expects to hear while walking through the forest.

Many wrong answers on ACT English involve this error; you can very often get down to two answers and occasionally down to one just by crossing options that contain it.