For example,
If Bobby buys a pencil, an eraser, and a pad of paper, then he can write his essay.
To remove the ambiguity in the final comma, my instinct is to write:
If Bobby buys a pencil, an eraser, and a pad of paper; then he can write his essay.
Is this syntactically correct? Is there a preferred convention? Is there a general convention on replacing commas with other marks when they're ambiguous like this?
Best Answer
I assume by "ambiguous" you mean that the sentence could be interpreted as either:
Or:
But it's actually not ambiguous at all. "Then he..." cannot be interpreted as an item in the list, and since you say "and a pad of paper" instead of "and then a pad of paper", there is no implied sequence in which he must buy the items.
If you're just asking whether there's any need to change a comma to some other punctuation mark when multiple commas with different uses appear in the same sentence, the answer is also, generally speaking, no. The only time you'll see a comma turned to a semicolon in a list is when some of the items contain commas themselves: