12 Grammar: Adjective Clauses

An adjective describes a noun or noun phrase.

What is a clause?

A clause is a group of words that contain a subject and a verb. An independent clause is a complete idea; a simple sentence is an example of an independent clause. A dependent clause, however, is not a complete idea.

What is an adjective clause?

An adjective clause is a dependent clause that describes a noun or noun phrase. An adjective clause comes after the noun that it modifies.

Take another look

• My neighbor knows all of the quick and easy ways to get to the airport. He drives for both Uber and Lyft.
• My neighbor, who drives for both Uber and Lyft, knows all of the quick and easy ways to get to the airport.

How do you make an adjective clause?

To combine two separate sentences into a single sentence with an adjective clause, you must change the pronoun into a relative pronoun like that, who, or which. Pay attention to the position: The adjective clause follows the noun it describes. Look again at the sentence:

• My neighbor, who drives for both Uber and Lyft, knows all of the quick and easy ways to get to the airport.

Here’s another example:

• The car belonged to Young-Hee.
• I bought the car.

How can you combine this into one sentence using an adjective clause? (HINT: What is the same in both sentences? Car.)

Here are two possibilities:

• The car that I bought belonged to Young-Hee.
• I bought the car that belonged to Young-Hee.

There’s no difference in meaning. However, the focus changes. The first sentence focuses the reader’s attention on the car, while the second sentence focuses the reader’s attention on the person buying the car.

Which relative pronoun do you use?

Below are examples of the most common relative pronouns for adjective clauses.

[Carl is a student. He leaves near the ocean with his sister Paula.]

Paula, who doesn’t know how to swim, doesn’t like the ocean.

[Paula doesn’t like the ocean. She doesn’t know how to swim.]

[Somi is a swimming instructor. Carl knows her from high school.]

[Swimming lessons can help Paula. Somi teaches them every weekend.] (object)

They all decide to go to the community center, which has a pool.

[They all decide to go to the community center. It has a pool.] (subject)

[There are important lessons. Paula needs to learn them.] (subject)

Carl wants to tell Paula the news that she will pass the class.

[Carl wants to tell Paula news. She will pass the class.] (object)

[Somi is happy to help. Her first language is not English.]

[Later, Paula wants to swim somewhere. There are big waves there.]

Try it

INSTRUCTIONS: Combine the sentences using an adjective clause.

1. He was sitting in the emergency room. It was very crowded in there.
2. A nurse was nearby. He called to her.
3. The nurse took one look at the man and knew he needed a doctor. His color was not good.
4. She connected the man’s finger to a machine and left him for a minute while she checked another patient. The machine checked his blood oxygen levels.
5. Just then, a doctor walked by and noticed that the man had passed out. His finger was still in the machine.
6. The doctor took the man’s pulse and temperature and determined that the man likely had COVID and needed a ventilator. It could help him breathe.
7. The doctor gave the man an injection. It made him go to sleep.

Is the relative pronoun the subject or the object of the clause?

• Example: The city that she wants to visit most is Berlin.

The relative pronoun that is not the subject of the clause. There is the pronoun she before the verb in the clause, and she is the clause’s subject. The relative pronoun, that, connects the adjective clause back to the noun it describes, which is city. When the subject is not the relative pronoun, you can often delete it, like this: The city she wants to visit most is Berlin.

• Example: There are many drivers who passed a driving test but still do not follow all the traffic rules.

When the subject is the relative pronoun, however, you can’t delete it. In the example above who is the subject for the verb passed in the adjective clause. So this adjective clause cannot be reduced (made shorter).

What punctuation do you need to use with an adjective clause?

Generally, if the adjective clause is helping to identify the noun it describes, then you do not use commas to set it apart.

However, if the adjective clause is only helping to describe the noun but is not identifying it, then you use commas to set apart the adjective clause.

Don’t use commas with clauses that are defining, restrictive, or essential

• The woman who is wearing the brown dress teaches Spanish.
• This man lives in the same apartment where my brother used to live.

In the first sentence, as well as describing the man, the adjective clause who wears a brown dress helps the reader identify exactly which man the writer is talking about. Similarly, in the second sentence, the clause where my brother used to live helps to identify in which house the man lives.

In other words, you use an adjective clause without commas when it both describes and identifies the noun. The information is essential to the sentence.

Use commas with clauses that are nondefining, nonrestrictive, nonessential

• Gabriel Reyes, who is from Mexico, wrote that book last year.
• The Japanese Garden, which is in Portland, includes many smaller gardens.

Try it

INSTRUCTIONS: Read each sentence. Add commas where necessary.

1. The new coronavirus which causes the disease COVID-19 has infected millions of people globally.
2. The disease was first detected in Wuhan where 11 million residents have been living isolated in quarantine for months.
3. The disease is spread by droplets which are sprayed into the air when an infected person coughs or sneezes.
4. Infection can be transmitted if a person touches objects or surfaces that an infected person has coughed and sneezed on and then touches their mouth, nose, or face.
5. Many people who carry and spread the disease show few or no symptoms.
6. For people whose health is already impacted by heart disease, diabetes, or other underlying conditions, COVID-19 can be very deadly.

Are there rules for adjective clauses?

Explanation: This one forgot to include the relative pronoun “which”, and it is wrong because there’s no subject for the verb “give”.

When can you use adjective clauses in your writing?

To connect ideas or to avoid short sentences

• Weaker: The road went to the top of the mountain. It was difficult to use in the winter.
  
• Stronger: The road, which was difficult to use in the winter, went to the top of the mountain. (or) The road, which went to the top of the mountain, was difficult to use in the winter.

To describe a person

• Weaker: George Spelvin was an actor. He liked to perform in comedies.
• Stronger: George Spelvin was an actor who liked to perform in comedies.

To make writing more concise and more academic

• Weaker: A hashtag begins with the # symbol. It is a label. The label is used on social media sites. The label makes it easier to find posts. Those posts contain specific information or content.
• Stronger: A hashtag, which begins with the # symbol, is a label that is used on social media sites and which makes it easier to find posts that contain a specific information or content.

Did you notice? There are four adjective clauses in the one sentence above! One describes hashtag, two describe label, and one describes posts.

What are some common errors that writers make with adjective clauses?

Here’s one …

• Incorrect: There is an idiom in English: The family plays together stays together.
• Correct: There is an idiom in English: The family that plays together stays together.

Remember to use use a relative pronoun in the subject position.

Here’s another …

• Incorrect: Oregon, that started as a territory, became a state in 1859.
• Correct: Oregon, which started as a territory, became a state in 1859.

Use who, that, or whom for people and that or which for things. Do not use that in nonrestrictive clauses. Do not use whom in a subject adjective clause.

Here’s one more …

• Incorrect: Many people who they have cats also have dogs.
• Correct: Many people who have cats also have dogs.

In an adjective clause, do not include a pronoun that refers to the modified noun.