Periods

You know how to use periods. We get it, but hear us out.

Using punctuation vs. understanding punctuation

Knowing how to use something isn’t the same as understanding how it works. And for the ACT, you have to know how each punctuation mark functions grammatically.

For example, you and I may know how to use a computer but have no idea how the electronics inside that computer function. Similarly, we may know how to send a text message while being totally ignorant about the technology that moves a text message from our phone to someone else’s.

Understanding punctuation on the ACT

To do well on the ACT English exam, you need to know more than just how to use punctuation; you have to know their rules. When you know the rules, you’ll be able to answer EVERY punctuation question correctly.

Let’s start with a definition of the period first: a period is a punctuation mark used to end a declarative sentence (a sentence that declares something). If a sentence isn’t claiming something, it’s usually asking something, in which case we’d use a different punctuation mark.

Definitions

Period

A punctuation mark used to end a declarative sentence

ACT period checklist

So, since you’re probably up to speed about using a period, let’s get into the specific rules of the period. Knowing when and how to use a period comes down to knowing what a complete sentence is.

Here’s a checklist you can use to determine if what you’re reading is a sentence. You need three things to have a complete sentence:

1. Subject
2. Verb
3. Complete Thought

Example

Walking slowly, the policeman kept a sharp eye.

The subject-verb set here is “policeman-kept” since “kept” is an action, and “policeman” is the person or thing that did it.

We might mistake “walking” as a verb, but notice that there is no subject to go with it (“policeman” can’t go with “walking” because it’s too busy going with “kept”!)

Therefore, this sentence expresses a complete thought, has a subject-verb set, and can close with a period.

Using the period to connect sentences

Here is the period rule you’ll encounter the most on the ACT:

Periods connect complete sentences.

Let’s go through some examples to illustrate this.

Example

Let’s say we have two sentences we’d like to connect.

Sentence 1: He likes red

Sentence 2: She likes blue

If we put a period between them, we connect the two sentences (see below).

He likes red. She likes blue.

Here we have a period connecting two sentences together.

When you take the ACT English test, you’ll often need to choose the correct punctuation to connect sentences.

Easy enough, right? Don’t be so sure…

Period trap

The ACT English test will trick you into thinking something is a sentence when it isn’t.

Here’s an example of how the ACT English Test will try and trick you.

Example

While I can’t stand politics during the presidential elections. I love the memes that come from it.

1. NO CHANGE
2. elections, I

We have to choose between a period and a comma in these options. While we haven’t gone over the comma rules yet (we’ll learn this in the chapter Linking dependent clauses), we don’t need to know them to answer this question.

All we have to do is use the checklist we learned.

ACT tip

You need three things to have a complete sentence:

1. Subject
2. Verb
3. Complete Thought

Here we have two clauses (remember, a clause is just a clump of text that has a subject and a verb). Let’s look at the clauses below and see if both clauses are sentences. If both clauses are sentences, we know we need to use a period.

Clause 1: While I can’t stand politics during the presidential elections

Clause 2: I love the memes that come from it

Let’s take a look at Clause 1 first.

Remember, all we have to do is use the complete sentence checklist.

1. Subject: Does Clause 1 have a subject?

2. Verb: Does Clause 1 have a verb?

3. Complete Thought: Does Clause 1 have a complete thought?

A clause must meet all three points on the checklist for a clause to be a sentence. So, since we know Clause 1 is not a complete sentence, we know we can’t put a period after it.

See if you can answer the following question by yourself.

Exercise

There are hundreds of millions of stars in our galaxy. Our sun is just one of them.

A. NO CHANGE
B. galaxy, our

Pick the correct answer using the sentence checklist.

Remember, just use the sentence checklist to make sure you’re using the period correctly. Then, you should be in good shape on test day if you use it.

Key points

You need three things to have a complete sentence:

1. Subject
2. Verb
3. Complete Thought