Question

Waiting for the bus to arrive, Joel finished doing his homework, he was so bored that he finished all his homework.

Listening to the sentence, you will think that there is nothing wrong with it. However, once you read it and look at it closely, you will realize that it is awkward and grammatically incorrect. This sentence is a good example of a comma splice. What is a comma splice?

Comma splices, also called as run-on sentences, result when two independent clauses are connected with a comma incorrectly. As a review, independent clauses are clauses that are made up of a subject and a verb that conveys a complete thought.

Going back to the sentence:

Waiting for the bus to arrive, Joel finished doing his homework, he was so bored that he finished all his homework.

There are three ways in which this sentence can be grammatically correct and accepted.

Separate it with a period.

Waiting for the bus to arrive, Joel finished doing his homework. He was so bored that he finished all his homework.

 

Connect the independent clauses with a coordinating conjunction (for, and, nor, but, or, yet, so).

Waiting for the bust to arrive, Joel finished doing his homework, for he was so bored that he finished all his homework.

 

Use a semicolon to separate the two independent clauses.

Waiting for the bus to arrive, Joel finished doing his homework; he was so bored that he finished all his homework.

 

Opt for a subordinating conjunction like when, while, before, after, as soon as, once, since and etc. by using a subordinating conjunction, the other independent clause becomes a dependent clause.

Waiting for the bus to arrive, Joel finished doing his homework because he was so bored that he finished all his homework.

Here are more examples:

1. Even though everybody was prepared for it, the storm still caused extensive damage, power is out all over the city.

1. Even though everybody was prepared for it, the storm still caused extensive damage. Power is out all over the city.
2. Even though everybody was prepared for it, the storm still caused extensive damage, and power is out all over the city.
3. Even though everybody was prepared for it, the storm still caused extensive damage; power is out all over the city.
4. Even though everybody was prepared for it, the storm still caused extensive damage as power is out all over the city.

 

1. I went to the pharmacy, I needed to refill my prescription.

1. I went to the pharmacy. I needed to refill my prescription.
2. I went to the pharmacy, and I needed to refill my prescription.
3. I went to the pharmacy; I needed to refill my prescription.
4. I went to the pharmacy because I needed to refill my prescription.

Source of examples: http://dmc122011.delmar.edu/swc/exercises/Exercise_Key_Comma%20Splices.pdf

There are a lot of practice exercises online. Train your grammar skills and avoid comma splices in your IELTS writing.