Today’s grammar tip: Commas with conjunctions.
For commas and conjunctions, a lot of it comes down to the type of clause you’re working with.
If we’re connecting two independent clauses (meaning they can stand alone as two separate sentences if we wanted them to) with the conjunction and, but, or, so, or yet, then we should add a comma.
- My older dog, Audrey, loves to bark directly in children’s faces, and my younger dog, Peggy, prefers to lick their sticky hands. (We’re a hit at the dog park.)
- We tried making pizza from scratch, but I didn’t sprinkle the counter with enough cornmeal and the dough got stuck.
- My six-year-old nephew said his bedtime is ten o’clock, yet I have it on good authority that he should be asleep by eight.
Now for dependent clauses. If you have an independent clause followed by a restrictive dependent clause (meaning the information is essential to understanding the sentence), you do not need the comma. But if your independent clause is followed by a nonrestrictive dependent clause (meaning the information is just supplemental), you should add the comma.
- Restrictive: I will eat mushrooms only if I can’t see them. (NOT “I will eat mushrooms, only if I can’t see them.”)
- Nonrestrictive: I would prefer my salad without mushrooms, if you don’t mind.
Finally, let’s finish out with compound predicates (meaning two or more verbs or verb phrases that share the same subject – like multitasking). For sentences with compound predicates, you usually do not want to separate the subject from its verbs, so you do not need a comma.
- Patients may experience dizziness and should not drive or operate forklifts.
- I started working on a 5,000-piece puzzle but lost interest after finishing the border.
To summarize, ask yourself this: Have we changed or repeated the subject? If so, you need a comma between the clauses.