My textbook tells me I should use は as a negative particle. The example sentence is 私はお酒は飲みません。I asked my coworker about it and he couldn’t really explain it. He said that 私はお酒は飲みます is also ok. I want to say お酒を飲みません/ます which he says is fine. So what is my textbook trying to show me? There is no other explanation, just (negative particle). Halp!
If you have a negative sentence, は tends to appear more than を. It’s not a rule or anything. I think this is just an extention of the “contrast marker” role of は. As such, in an affirmative sentence, は and を are of course both possible, with を being more neutral, and は representing contrast.
So if this type of sentence shows up on the N4 exam, I choose は? Would they do that to me?
I don’t think something like
コーヒー (___) 飲みません A. は B. を C. が D. に
would show up on an exam. Because it’s not clear enough of a distinction between を and は for it to be considered “right or wrong.” But they might do something without the を option.
お酒は飲みません, “As for alcohol, I won’t drink it.” (I drink other things, but not alcohol) = “I don’t drink alcohol (in general).”
お酒を飲みません, “I won’t drink (the) alcohol.”
It just tends to be that the を is used more often for a concrete object such as one that’s offered to you, while using は is describing what you will/won’t do in a more abstract way (if you read it as “As for…”, which I recommend).
I’m pretty sure this is simply convention. Either way can be used in the negative, just as either way can be used for the positive ます.