When a term like However, As a result, or Consequently starts a sentence, it should be followed by a comma. (These terms are called transitional phrases.)|
A transitional phrase sits at the start of a sentence and acts like a bridge to an idea in the previous sentence. Common ones are However, Consequently, Therefore, and As a result.
A transitional phrase is followed by a comma. A transitional phrase is never preceded by a comma.
Use a Comma after a Transitional Phrase (e.g., However,)It is common for a sentence to start with an introduction that acts like a bridge between the last sentence and the new sentence. The introduction makes the transition between the two sentences smoother. (It is known as a transitional phrase.)
A transitional phrase always appears at the start of a sentence and is followed by a comma. For example:
Beware Putting a Comma before HoweverThe word However is a very common transitional phrase. It is just like the other transitional phrases, but it deserves a special mention because writers often mistakenly precede it with a comma (as opposed to using it to start a sentence).
On occasion, it might be appropriate to precede however with a semicolon. For example:
YOU CAN USE SEMICOLONS
On occasion, you may wish to use a semicolon before a transitional phrase to make the transition between sentences even more seamless. For example:
DON'T OVERUSE SEMICOLONS
Transitional phrases are useful because they keep ideas flowing between sentences. Most of them should be preceded by full stops / ( periods.
If you use semicolons before all your transitional phrases, you will annoy your readers. Semicolons are great in moderation. Hold them back for when you want a really smooth transition between two sentences.
NOT A COMMA
You cannot use a comma before a transitional phrase. For example:
Read more about the error known as a run-on sentence.