Tôi gắng làm xong việc.

It is understandable, but many speakers would find it a little less natural than:

• Tôi cố gắng làm xong việc.
• Tôi cố làm xong việc.

Using gắng by itself is possible, but cố gắng is much more common in everyday standard Vietnamese. So as a learner, cố gắng is usually the safer choice.

Gắng means something like to try hard, to make an effort, or to strive.

In this sentence, it shows that the speaker is making an effort to complete the task. It adds a sense of effort, not just intention.

Compare:

• Tôi làm xong việc. = I finish the work / I finished the work.
• Tôi gắng làm xong việc. = I try hard to finish the work.

Again, in modern everyday speech, cố gắng is much more common than gắng alone.

This is normal in Vietnamese. Vietnamese often puts verbs next to each other without needing a word like to.

So:

• gắng = try, make an effort
• làm xong = finish doing

Together, gắng làm xong việc means try to finish the work.

English needs to in try to finish, but Vietnamese does not.

Làm xong is a very common pattern.

• làm = do
• xong = finished, completed

When xong comes after a verb, it often shows that the action is completed. So:

• làm xong = do something until it is finished / finish doing
• ăn xong = finish eating
• viết xong = finish writing

In your sentence, làm xong việc means finish the work.

In sentences like this, xong is often described as a result complement or a word showing the completed result of the action.

So in làm xong việc, it does not act like a completely separate main verb. Instead, it tells you the result of làm: the work gets done completely.

A useful way to think about it is:

• làm = do
• làm xong = do completely / finish doing

Vietnamese verbs do not change form for tense the way English verbs do.

So Tôi gắng làm xong việc by itself does not clearly mark present, past, or future. The time usually comes from context or from time words such as:

• đã = past
• đang = ongoing
• sẽ = future

Examples:

• Tôi đã cố gắng làm xong việc. = I tried / I made an effort to finish the work.
• Tôi đang cố gắng làm xong việc. = I am trying to finish the work.
• Tôi sẽ cố gắng làm xong việc. = I will try to finish the work.

Việc means work, task, job, or matter, depending on context.

In làm xong việc, it usually means the work or the task at hand. Vietnamese often leaves out words like the, a, or my when the meaning is clear from context.

So việc here could be understood as:

• the work
• my work
• the task
• the task I need to do

The exact meaning depends on the situation.

Vietnamese does not use articles like a, an, and the the way English does.

That means a bare noun like việc can often mean:

• work
• the work
• my work
• the task

Context tells you which one is intended.

If the speaker wanted to be more specific, they could say things like:

• công việc này = this work / this task
• việc của tôi = my work
• công việc đó = that work / that job

Yes — and for most learners, that is the better and more standard version.

• Tôi cố gắng làm xong việc.

This sounds very natural and is probably what you should use in most situations.

A rough comparison:

• gắng = try hard, strive; possible, but less common alone
• cố = try, make an effort
• cố gắng = try hard / make an effort; very common and standard

So if you are unsure, use cố gắng.

Not exactly.

Tôi gắng làm xong việc means the speaker is trying or making an effort to finish the work. It focuses on the effort, not necessarily the successful result.

If you want to say I managed to finish the work, Vietnamese would more naturally use something that shows success, such as:

• Tôi đã làm xong việc. = I finished the work.
• Tôi đã xoay xở làm xong việc. = I managed to finish the work.
• Tôi đã cố gắng và làm xong việc. = I tried hard and finished the work.

So gắng does not by itself guarantee success.

Some parts can change a little, but not all changes are natural.

Natural:

• Tôi cố gắng làm xong việc.
• Tôi gắng làm xong việc.

Not natural:

• Tôi làm gắng xong việc.
• Tôi gắng xong việc.

That is because gắng normally comes before the action you are trying to do, and xong normally comes after the main action verb to show completion.

So the basic pattern is:

subject + try/make effort + verb + xong + object

Yes, they are similar in meaning but different in style.

• làm xong việc = finish the work; common, everyday, conversational
• hoàn thành công việc = complete the work; more formal, more written, more official-sounding

Examples:

• Tôi cố gắng làm xong việc hôm nay. = I’m trying to finish the work today.
• Tôi cố gắng hoàn thành công việc hôm nay. = I’m trying to complete the work today.

Both are correct, but làm xong việc sounds more natural in ordinary speech.

Gắng is pronounced with:

• g as a Vietnamese g sound
• ă as a short vowel
• ng at the end, like the ng in sing
• the sắc tone, which is a rising tone

So the important thing for learners is:

• keep the vowel short
• end with ng
• use a rising tone

If you already know cố gắng, then this is the same gắng from that expression.