Learn Hardcore Chinese: wǒmen yìzhí zài xuéxí, xiàwǔ cái chī wǔfàn. - We were studying the whole time and only ate lunch in the afternoon.

一直 means “continuously/throughout (a stretch of time).” It stresses an unbroken duration. Without it, 我们在学习 just says “we are studying” (snapshot). With 我们一直在学习, you highlight that the studying kept going for a while. You can say 我们一直学习 too; see below for 在 vs no 在.

Why is 在 before 学习? Is it location or grammar?

Here 在 is the progressive marker (ongoing action), not the location preposition. 在+V ≈ “be V‑ing.” So 在学习 = “studying (right now/over that period).”

Which is better: 我们一直学习 or 我们一直在学习?

Both are grammatical.

我们一直在学习 highlights the progressive aspect (you picture the ongoing action).
我们一直学习 can sound a touch more general/formal or narrative. In everyday speech, 一直在V is very common for “have been V‑ing.”

Can I use 正在 instead of 在?

我们正在学习 = “we are (right now) studying,” focusing on the present moment.
我们一直在学习 = “we’ve been studying (continuously),” focusing on duration. Avoid 一直正在 together; it’s redundant/awkward.

What exactly does 才 do here?

才 before the verb means “not until/only then,” signaling something happened later than expected. 下午才吃 implies lunch happened late (not at the usual time).

Can I use 就 instead of 才?

No—the meaning flips.

才 = later than expected: 下午才吃 “not until the afternoon did (we) eat.”
就 = earlier/sooner/easily: 中午就吃 “(we) ate as early as noon.”

Where can I put 下午 in the sentence?

All of these are natural, with small differences in emphasis:

下午，我们才吃午饭。
我们下午才吃午饭。 Avoid 我们才下午吃午饭 for this meaning; 才 should sit before the verb phrase it modifies, not before the time word.

Does the comma work like “because/so” here? Should I add a connector?

Chinese often links related clauses with a comma without an explicit conjunction. The cause/result is clear from context. You could add 所以/于是 for clarity: 我们一直在学习，所以下午才吃午饭。

Do I need 了 after 吃午饭 to show it’s completed?

Not required. 下午才吃午饭 already presents a completed event in a completed time frame. You may add 了 (下午才吃了午饭) to stress completion, but it’s optional and context‑dependent.

Is “afternoon lunch” odd in Chinese?

No. 下午才吃午饭 is exactly how you say you ate lunch unusually late (in the afternoon). The oddness is the lateness, which 才 already conveys.

What’s the difference among 午饭, 午餐, 中饭, and 中餐?

午饭/午餐 = lunch. Both are common; 午餐 is a bit more formal.
中饭 also means lunch (regional/informal).
中餐 in Mainland usage usually means “Chinese cuisine” (not “lunch”). In Taiwan, 中餐 can mean “lunch,” but that’s region‑specific. Safest for “lunch”: 午饭/午餐.

Could I just say 吃饭 instead of 吃午饭?

吃饭 means “have a meal” in general. If you want to be clear it’s lunch (and to preserve the “late for lunch” nuance), keep 午饭. 下午才吃饭 is understandable but less specific.

Pronunciation/tone tips for this sentence?

一直: yìzhí (一 before a 2nd tone stays yì).
在: zài (4th tone).
学习: xuéxí (2–2).
下午: xiàwǔ (4–3).
才: cái (2).
午饭: wǔfàn (3–4). Mind third‑tone sandhi where applicable in longer phrases; nothing tricky here beyond standard patterns.

Is 学习 the best verb here? What about 读书 or 上课?

学习 = study/learn (neutral and broad).
读书 can mean “study/read/be a student,” slightly more colloquial.
上课 = “attend class.” All can work depending on context: 一直在学习/读书/上课.

Can I add 都: 我们一直都在学习?

Yes. 一直都 adds emphasis. It can mean:

Over the entire period, without exception: “we’ve been studying the whole time,” or
If the subject is plural, it can also suggest “all of us have consistently been studying,” depending on context.

What if I want to say “we hadn’t eaten lunch until the afternoon” (emphasizing the lack up to that point)?

Use a negative‑perfect construction:

我们到下午都还没吃午饭。 or
一直没吃午饭，到了下午才吃。 Note: 才不 is an emphatic “definitely not,” not the temporal “not until.”

Can I say 到/直到下午才吃午饭?

Yes:

到下午才吃午饭 or 直到下午才吃午饭 both intensify the “not until (that time)” meaning.

Where does 才 go if there’s a modal like 会/能?

才 comes before the modal/verb phrase:

我们下午才会吃午饭。 (We won’t eat until the afternoon.)
我们下午才能吃午饭。 (We can’t eat until the afternoon.)

Could I replace 才 with 然后 to mean “and then”?

然后 only marks sequence, not lateness. 一直在学习，然后下午吃午饭 = “studied, and then ate in the afternoon,” but it drops the “later than expected/not until” nuance that 才 gives.