Learn Hardcore Chinese: zǎoshang wǒ yìbiān hē chá, yìbiān kàn shū. - In the morning I drink tea while reading.

It expresses two actions happening at the same time by the same subject. Structure: [Subject] + 一边 + V1 (+ object) ，一边 + V2 (+ object). Here: 我一边喝茶，一边看书 = I drink tea while reading.

Do I have to repeat 一边? Can I say 我一边喝茶，看书?

In casual speech, dropping the second 一边 is common: 我一边喝茶，看书. In careful writing or as a learner, repeating 一边 is clearer and preferred. Don’t keep only the second one.

Does the order of the two actions matter?

Both actions are simultaneous, so basic meaning doesn’t change. Native speakers often put the more important or “main” action second. If reading is the main activity and tea is incidental, keep 看书 second.

Why is the subject 我 only said once? Should I repeat it before the second 一边?

No need. The subject before the first 一边 controls both clauses. Repeating 我 before the second 一边 is redundant.

Where does the time word go—why is it 早上我... and can I say 我早上...?

Time words typically come before the verb phrase. They can appear either before or after the subject: 早上我... and 我早上... are both natural. With a specific time you can also front it with a pause: 今天早上，我一边喝茶，一边看书. Don’t add 在 before time words in everyday speech (say 早上, not 在早上).

Why is 上 in 早上 neutral (zǎoshang) instead of fourth tone?

In time-of-day compounds like 早上 (zǎoshang) and 晚上 (wǎnshang), the second syllable is often neutral in Mainland standard, reflecting reduced stress. You’ll still hear a clear fourth tone from some speakers; both are understood. Contrast 上午 (shàngwǔ), where 上 is fourth tone.

Why is 一 pronounced yì in 一边 (yìbiān)?

Tone sandhi: 一 (yī) changes to:

yí before a fourth-tone syllable (e.g., 一样 yíyàng),
yì before a 1st/2nd/3rd-tone syllable (e.g., 一边 yìbiān, 一点 yìdiǎn). Since 边 (biān) is first tone, it becomes yìbiān.

Can I add 在/正在 to show it’s happening right now?

You usually don’t need them with 一边...一边...; simultaneity already suggests an ongoing action. To make “right now” explicit, add a time word: 我现在一边喝茶，一边看书. If you do use the progressive marker, put it before each verb: 我一边在喝茶，一边在看书—grammatical but wordy.

Is this sentence a habit or a one-time event?

It’s flexible. Without aspect markers, 早上我一边喝茶，一边看书 can mean:

Habit: “In the mornings I usually...” (add 常常/经常 to make it explicit)
A specific time: add a time anchor like 今天早上/昨天早上.

Why no measure words—why not 喝一杯茶 / 看一本书?

For general/unspecified actions, VO phrases don’t need measures: 喝茶, 看书. Use measures for specific amounts: 我早上常常一边喝一杯茶，一边看一本书. To avoid heaviness, many speakers quantify just one object: 一边喝一杯茶，一边看书.

Does 看书 mean “read a book” or “study”? What about 读书?

看书: “read (books),” often neutral; in context it can imply quiet study.
读书: “to read; to study; to attend school.” 我在读书 often means “I’m a student.”
In this sentence, 看书 just means reading.

Can different subjects do the two actions? For example, “I drink tea while my friend reads”?

No. 一边...一边... expects the same subject for both actions. For different subjects, use something like 我喝茶，朋友同时看书 or 我喝茶，而朋友看书.

Are there other natural ways to say “do A while doing B”?

Yes:

我喝着茶看书。 (着 zhe marks an accompanying/background action)
我边喝茶边看书。 (colloquial variant without 一)
我一面喝茶，一面看书。 (more formal/literary)
我喝茶的同时看书。 (formal “at the same time”)

Why is there a comma before the second 一边? Do I always need it?

The comma mirrors a natural pause between the two parallel verb phrases. Both versions are fine: 我一边喝茶，一边看书。 (with comma) and 我一边喝茶一边看书。 (no comma). Use whichever matches your style and reading rhythm.