Learn Hardcore Japanese: simekiri made ato itiniti sika nai kara, konya ha asobenai. - There’s only one day left until the deadline, so I can’t hang out tonight.

まで = until/up to. It marks the endpoint of a span. In 締め切りまであと一日, you’re measuring the time remaining “until the deadline.”
までに = by (a deadline by which something must be done). Use it when talking about completing an action by a time.
- Example: 締め切りまでに終わらせます (I’ll finish it by the deadline). Saying 締め切りまでにあと一日しかない is unnatural because you’re not describing an action deadline; you’re measuring time left.

What is あと doing in あと一日?

あと means “remaining/left.” Before amounts or counters, it indicates how much is left: あと三分 (three minutes left), あと少し (a little more). Here, あと一日 = one day left. Note that あと can also mean “later” in expressions like あとで (later), but here it’s “remaining.”

Why do we need しか plus a negative (ない)?

しか attaches to what’s being limited and must be followed by a negative predicate. It means “only (and nothing more)” with a nuance of insufficiency.

一日しかない = There is only one day (and that’s all).
Ungrammatical: 一日しかある. Other examples:
お金しかない (I have only money [no cards/cashless]).
彼しか来なかった (Only he came).

How is しか different from だけ?

だけ = “only” (neutral). No requirement for a negative.
- 締め切りまであと一日だけある = There is only one day left (neutral statement).
しか
- negative = “only and that’s not enough/limiting.”
  - 締め切りまであと一日しかない emphasizes the shortage. In your sentence, because the result is 遊べない, しか matches the feeling of “not enough time, so I can’t.”

What is the subject of ない in あと一日しかない?

It’s omitted, as is common in Japanese. Implicitly it’s “days/time.” You can think of it as （日が）あと一日しかない = “(There are) only one day (left).” In the second clause, the subject is also omitted and understood as “I/we”: 今夜は（私は）遊べない.

Which ない is this? Is it the negative of ある?

Yes. ある (to exist/there is) → ない (there isn’t). あと一日しかない literally means “there isn’t more than one day left.”

Can you end a sentence with から?

Yes. から marks a reason/cause and can come mid-sentence (reason → result) or end a sentence as a trailing justification.

Full: 締め切りまであと一日しかないから、今夜は遊べない。
Trailing: 今夜は遊べない。締め切りまであと一日しかないから。 Ending with から is common in speech to give a reason after the fact.

Why is は after 今夜?

は marks the topic: “As for tonight.” It sets tonight as the frame of discussion. It can also carry a slight contrastive nuance (“tonight (at least) I can’t, though other times might be different”). Without は, 今夜、遊べない is also possible and a bit more matter-of-fact.

Why use 遊べない (can’t play/hang out) instead of 遊ばない (won’t play/hang out)?

遊べない is the negative potential form of 遊ぶ and expresses inability/unavailability due to circumstances (“can’t”).
遊ばない is plain negative and often sounds like a choice or refusal (“won’t/don’t”). Here, the lack of time is the cause, so 遊べない fits better. Formation note (Godan verbs): change the final consonant to the e-row + る → 遊ぶ → 遊べる → 遊べない.

How do you read 一日 here?

Read it いちにち (“one day” as a duration). Be careful not to read ついたち, which is used for dates (“the 1st of the month”).

Could I use 締め切りまでに here instead of 締め切りまで?

Not in this structure. You’re stating the amount of time remaining “until” the deadline, so まで is correct. Use までに when pairing with an action verb about completing something by that time:

締め切りまでに提出しなきゃ (I must submit it by the deadline).

What’s the difference between あと一日 and もう一日?

あと一日 = one day remaining (time left until some endpoint).
もう一日 = one more day (in addition to what you already have/need). Examples:
締め切りまであと一日 (There’s one day left until the deadline).
もう一日ください (Please give me one more day).

How does まだ fit in (vs. もう and あと)?

まだ = still/yet.
- まだ一日ある = There’s still one day (left).
- まだ一日しかない = We still have only one day (emphasizes insufficiency; can sound a bit exasperated).
もう = already/anymore; also “one more” when with counters (もう一日).
あと = remaining/left. Choose based on the nuance you want (neutral “left,” additive “one more,” or “still”).

Can I replace から with ので? Any nuance difference?

Yes. ので is softer/more objective and a bit more formal/polite than から.

Polite: 締め切りまであと一日しかありませんので、今夜は遊べません。 In casual speech, から is more common.

Where does しか attach? Can it follow verbs?

With nouns/counters/phrases, しか attaches to what’s being limited: あと一日しかない, これしかない, 彼にしか言わない.
With verbs in dictionary form + しかない, it means “have no choice but to …”: やるしかない (there’s nothing to do but do it). Don’t confuse this with the counting use.

Is the spacing and punctuation in the example normal?

Spaces are added for learners; standard Japanese doesn’t use spaces between words. Commas (、) are optional and used for readability. The sentence would normally appear as: 締め切りまであと一日しかないから、今夜は遊べない。

Could I say 行けない instead of 遊べない?

Depending on context:

行けない = can’t go (to the meetup/event/venue).
遊べない = can’t hang out (can’t engage in leisure). If friends invited you somewhere specific, 今夜は行けない is natural. If it’s about hanging out in general, 今夜は遊べない fits well.

How would I make the whole sentence more polite or more casual?

More polite: 締め切りまであと一日しかありませんので、今夜は遊べません。
Casual (spoken): 締め切りまで、あと一日しかないから、今夜は遊べない。 or even 明日締め切りで、もう時間ないから、今夜は無理。