Learn Hardcore Chinese: wǒ jīngcháng wǎnshang zài fángjiān lǐ kàn diànyǐng. - I often watch movies in my room at night.

我经常晚上… = “I often, in the evenings, …” (emphasis a bit more on “often”)
我晚上经常… = “In the evenings, I often …” (emphasis a bit more on “evenings” as the time frame)

But in everyday conversation, both feel very natural; the difference is tiny. The main rule: 经常 usually goes after the subject and before the verb phrase (which can include time/place).

Why is there no 在 before 晚上? Why not 我在晚上经常在房间里看电影?

In Chinese, bare time words (like 晚上，明天，星期一) usually do not need 在:

我晚上在房间里看电影。 = “I watch movies in my room in the evening.”

Using 在 before a time word is possible but much less common and often more formal or contrastive:

我在晚上工作，在白天休息。
(Here 在 emphasizes the contrast between “during the evening” and “during the day”.)

For simple statements of when something happens, just the time word is normal:

我星期天看电影。 (not usually 我在星期天看电影 in everyday speech)

What exactly do 在 and 里 do? Could I say 我经常晚上房间里看电影 or 我经常晚上在房间看电影?

在 marks the location or time where an action happens.
里 means inside, making the place more specific.

在房间里 = “in the room” (inside the room)
在房间 = “at the room” (often still understood as “in”, but a bit less explicit)

Your options:

我经常晚上在房间里看电影。 ✅ very natural
我经常晚上在房间看电影。 ✅ also fine; just slightly less “inside”-focused
我经常晚上房间里看电影。 ❌ sounds wrong — you need 在 before the place phrase

General pattern:
在 + place (+ 里/上/下/旁边…) + Verb

So 在 is necessary; 里 is optional but common and natural here.

Why is there no word for “am / do / is” like 是 in this sentence? In English we say “I often watch…”.

Chinese verbs don’t use a separate “do” or “am” helper like English.

English: I often watch movies.
Chinese: 我经常看电影。 (just subject + adverb + verb)

The verb 是 is only used as a linking verb (A 是 B), like:

他是老师。= “He is a teacher.”

You do not use 是 directly before another action verb:

❌ 我是看电影
✅ 我看电影 = “I watch movies.”

So in 我经常晚上在房间里看电影, 看 already carries the meaning “watch”; no extra “do / am” is needed.

What’s the difference between 房间 and 房子? Could I say 在房子里看电影 instead?

Yes, you can say 在房子里看电影, but it means something slightly different.

房子: the house / building
房间: the room (inside a house, apartment, etc.)

So:

在房间里看电影 = watch movies in (my/your/etc.) room
在房子里看电影 = watch movies inside the house (not outside)

In the original sentence, 房间 is more natural if you mean “in my room”.

How are 晚上 (wǎnshang) and 里 (lǐ / li) pronounced? Why is it written wǎnshang instead of wǎnshàng?

Two things are happening:

晚上
- Dictionary tones: wǎn shàng (3rd + 4th)
- In real speech, the second syllable 上 in 晚上 usually becomes a neutral tone, so we write it wǎnshang.
- So you’ll hear wǎn·shang, not a strong 4th tone.
里
- Basic tone: lǐ (3rd tone)
- In many common phrases, it can be pronounced with a neutral tone: li
  - e.g., 这里 (zhèli), 那里 (nàli), 房间里 (fángjiān·li)

So you’ll often hear:

晚上在房间里 ≈ wǎn·shang zài fángjiān·li
with shang and li both quite light.

How does Chinese show tense here? How do I know if it’s “I often watch” or “I often watched / used to watch”?

Chinese verbs don’t change form for tense. 我经常晚上在房间里看电影 is time-neutral by itself.

The default reading is usually about habit / general truth in the present:

“I often watch movies in my room in the evenings.”

To show past or other nuances, Chinese typically uses time words or aspect particles:

Past habit (clear past time):
- 以前我经常晚上在房间里看电影。
  “In the past I often watched movies in my room in the evenings.”
Completed experience:
- 我经常在房间里看过电影。 (less common; sounds like “have often had the experience of watching movies in the room.”)

But for a simple “I often watch… (these days)”, 我经常晚上在房间里看电影 is enough.

What’s the difference between 经常 and 常常? Could I replace 经常 with 常常?

Yes, you can say:

我常常晚上在房间里看电影。 ✅

Both 经常 and 常常 mean “often / frequently” and are largely interchangeable.

Subtle differences (not strict rules):

经常 can sound a bit more neutral or slightly formal, and is very common in both speech and writing.
常常 can feel a bit more spoken / casual, or slightly more emotional in some contexts.

In everyday conversation, most people don’t feel a strong difference:
我经常… ≈ 我常常…

Why is it 看电影 and not just 看? Does 看电影 mean specifically “watch movies (as a full activity)”?

看 simply means “to look / to see / to watch / to read” depending on the object.

You usually need an object to show what you are watching/reading:

看电影 = watch movies
看书 = read books
看电视 = watch TV
看手机 = look at (your) phone

If you say only 我经常看, it feels incomplete, like “I often watch/read (something)” with the object missing, unless it’s very clear from context.

So 看电影 makes it explicit that the activity is “watch movies”.

Why is there no measure word like 部 before 电影? How do I say “a movie” vs “movies” in Chinese?

In Chinese, uncounted nouns can be singular or plural depending on context.
看电影 can mean “watch a movie”, “watch movies”, or “watch (some) movies”.

If you want to be explicit:

看一部电影 = watch one movie
看很多部电影 = watch many movies
Common measure words for 电影: 部, 场, sometimes 个 in casual speech.

In your sentence, the focus is the habit, not the exact number, so 看电影 without a measure word is very natural.

Where is “my” in “in my room”? Why doesn’t the Chinese say 在我的房间里?

Chinese often omits possessive pronouns like “my”, “your”, “his” when the owner is obvious from context.

Here, the subject is 我 (“I”), so 房间 will naturally be understood as “my room”, unless context says otherwise.

我在房间里。
Normally interpreted as “I’m in my room.”
If you specifically need to clarify it’s someone else’s room, you add the possessive:
- 我在他(的)房间里。 = I’m in his room.
- 我在你(的)房间里。 = I’m in your room.

So 在房间里 is enough in most cases to mean “in my room” when 我 is the subject.

Can I drop some parts of the sentence, like 我 or 晚上 or 在房间里, and still be correct?

Yes. Chinese often drops information that is clear from context.

Starting from the full sentence:
我经常晚上在房间里看电影。

Possible shorter versions:

If everyone knows you’re talking about yourself, you can drop 我:
- 经常晚上在房间里看电影。
If the time is clear (e.g. already talking about evenings), you can drop 晚上:
- 我经常在房间里看电影。
If the place is clear, you can drop 在房间里:
- 我经常晚上看电影。

The core is:

我看电影。 = “I watch movies.”

Then you add optional details (frequency, time, place):

frequency: 经常
time: 晚上
place: 在房间里

The more context people share, the more you can safely omit.