Having some trouble on the comma rule with the word "usually". If it is used in the beginning of the sentence would you put a comma after it? For instance, in the sentence, "Usually castles sat on a hilltop and had high stone walls." Would you put a comma after "usually" since it seems like an introductory word? Thanks.

I'd put a comma after "Usually" - yes.

When deciding whether to use a comma after the word "usually" at the beginning of a sentence, it's important to understand the purpose of using commas in general. Commas are used to indicate a pause or a separation of elements within a sentence.

In the case of the word "usually" at the beginning of a sentence, it depends on the specific situation. If "usually" is being used as an introductory word, you typically don't need to use a comma after it. This is because "usually" is not functioning as an introductory clause, but rather providing a general context for the rest of the sentence.

In your example sentence, "Usually castles sat on a hilltop and had high stone walls," you would not need to use a comma after "usually." The sentence flows naturally without a pause after "usually," and it still effectively introduces the general statement about castles.

However, it's important to note that there are instances where a comma could be used after "usually" if there is a need to create a pause or emphasize a particular point. It ultimately depends on the writer's intention and the specific sentence structure.

To summarize, in most cases, you would not need to use a comma after "usually" when it appears at the beginning of a sentence unless there is a specific reason or the sentence structure requires it. It's always helpful to read the sentence aloud to see if there is a natural pause or if the sentence flows smoothly without a comma.