Once and for all: When do you use a comma before “which,” “that, “or “who” in a sentence?

The turkey is almost gone, the stuffing a memory . . . time to resume talking about commas! Today we talk about when to set off phrases in commas . . . and when not to.

Whether or not you look forward to seeing your relatives . . . whether or not you eat turkey or are vegetarian . . . whether you adore the holidays or cannot wait until they are over . . . I thought you could use a Thanksgiving chuckle or two . . .

Sometimes we put commas around interrupting words. And then, sometimes we don’t. Do you know when to set words off with commas?

“As we were eating ants crawled all over our picnic blanket.” You might want a comma here!