1. When to use a comma before "except":
* When "except" introduces a contrasting element or exception:
* *Example:* "All the students passed the exam, except for John." (Here, "except for John" contrasts with the statement about all the students passing.)
* When "except" is used as a conjunction:
* *Example:* "I like all kinds of fruits, except for bananas." (Here, "except" functions like "but" or "although" to introduce a contrasting idea.)
2. When to omit a comma before "except":
* When "except" is part of a prepositional phrase:
* *Example:* "I have everything except the keys." (Here, "except the keys" acts as a prepositional phrase and is not a separate clause.)
3. When "except" is used as a part of a verb phrase:
* *Example:* "We except him from the meeting." (Here, "except" is part of the verb "except")
In general, it's helpful to think about whether "except" introduces a new idea or contrasts with a previous idea. If it does, a comma is usually needed.
Remember, there's no hard and fast rule, and the best way to determine if a comma is necessary is to consider the meaning and flow of the sentence.