"Let's go to karaoke tomorrow."
I was taught in college Japanese classes that は was optional with time clauses like 今日、あした、きのう, etc.
Why is the は necessary in this sentence? I didn't add it and got my sentence marked as wrong.
I didn't include は and my answer was accepted, so I guess Duolingo fixed it.
I had a feeling they would mark it wrong, so I added the は last minute.
The は is unnecessary in coloqual Japanese and and it sounds really innatural.