Sau khi giáo viên giải thích lại, Lan làm bài tập dễ hơn.

Sau khi means after and is used to introduce an event that happens earlier.

In this sentence:

• Sau khi giáo viên giải thích lại = After the teacher explained again / re-explained
• Lan làm bài tập dễ hơn = Lan did the exercise more easily

So sau khi + clause is a very common pattern for saying after X happened, Y happened.

Examples:

• Sau khi ăn xong, tôi đi ngủ. = After finishing eating, I went to sleep.
• Sau khi học bài, cô ấy xem TV. = After studying, she watched TV.

Vietnamese often does not mark tense the way English does. Verbs like giải thích and làm do not change form.

Instead, time is understood from:

• context
• time words
• sequence markers like sau khi

Here, sau khi already tells us one action happened before another. That makes the timeline clear even without a separate past-tense marker.

If needed, Vietnamese could add words like:

• đã for a completed action
• đang for an ongoing action
• sẽ for the future

For example:

• Sau khi giáo viên đã giải thích lại, Lan làm bài tập dễ hơn.

But in natural Vietnamese, leaving those out is very common when the meaning is already obvious.

Giải thích means to explain.

Lại here means again or once more, so:

• giải thích lại = explain again / explain one more time / re-explain

This use of lại is very common after verbs:

• đọc lại = read again
• viết lại = write again
• nói lại = say again
• làm lại = do again / redo

Be aware that lại can have other meanings in other contexts, but here it simply means again.

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

So giáo viên can mean:

• teacher
• a teacher
• the teacher

The exact meaning depends on context.

In this sentence, English would naturally say the teacher, because the situation suggests a specific teacher already known in context. But Vietnamese often leaves that unstated.

If a speaker wanted to be more specific, they might say:

• người giáo viên đó = that teacher
• cô giáo / thầy giáo = female teacher / male teacher

But giáo viên by itself is perfectly normal.

Vietnamese often repeats names more freely than English does.

In English, repeating a name too often can sound unnatural:

• Lan did this. Lan did that.

In Vietnamese, repeating the person’s name is very normal and often clearer than using a pronoun.

Also, Vietnamese pronouns depend heavily on:

• age
• relationship
• social role
• level of politeness

So using Lan avoids having to choose a pronoun and keeps the sentence simple and clear.

Làm bài tập literally means do exercises or do an exercise/task.

Depending on context, it can refer to:

• school exercises
• homework
• practice questions
• assignments

Breaking it down:

• làm = do
• bài tập = exercise / assignment / homework task

So làm bài tập is a very common school-related phrase. The most natural English translation depends on context:

• do the exercise
• do the homework
• complete the assignment

In this sentence, dễ hơn most naturally describes the way Lan did the exercise, so the idea is:

• Lan did the exercise more easily

Vietnamese often uses adjectives where English would prefer an adverb. So:

• dễ = easy
• dễ hơn = easier / more easily

Because dễ hơn comes after làm bài tập, it describes the action/result in a broad way, not necessarily the exercise itself.

If you wanted to focus more clearly on the exercise becoming easier, you might say something like:

• Bài tập trở nên dễ hơn. = The exercise became easier.

But as written, this sentence means that after the explanation, Lan was able to do the exercise with greater ease.

Hơn is the common word for forming comparisons in Vietnamese.

Pattern:

• adjective + hơn = more + adjective / -er

So:

• dễ = easy
• dễ hơn = easier / more easily

Other examples:

• nhanh hơn = faster
• khó hơn = more difficult
• tốt hơn = better

In this sentence, the comparison is implicit. Vietnamese does not need to say exactly than before if it is obvious from context.

So dễ hơn here means:

• easier than before
• more easily than before

If you want to state it explicitly, you could say:

• dễ hơn trước = easier than before

The comma separates the introductory time clause from the main clause.

Structure:

• Sau khi giáo viên giải thích lại, = after the teacher explained again
• Lan làm bài tập dễ hơn. = Lan did the exercise more easily

This is similar to English:

• After the teacher explained again, Lan did the exercise more easily.

The comma helps show the boundary between the two parts of the sentence. In informal writing, Vietnamese punctuation can sometimes be flexible, but this comma is natural and helpful.

Yes. Vietnamese can often place the main clause first and the sau khi clause later.

For example:

• Lan làm bài tập dễ hơn sau khi giáo viên giải thích lại.

This means essentially the same thing:

• Lan did the exercise more easily after the teacher explained again.

However, starting with sau khi... is very common when the speaker wants to emphasize the sequence of events or set up the context first.

Yes.

• giáo viên = teacher, gender-neutral
• cô giáo = female teacher
• thầy giáo = male teacher

So giáo viên is the most neutral and general word.

A speaker might choose:

• giáo viên when gender is unknown, unimportant, or they want a neutral tone
• cô giáo or thầy giáo when the teacher’s gender is known and relevant

In many classroom contexts, all three are possible depending on style and context.

No, you should not always translate lại as again automatically.

In this sentence, giải thích lại clearly means explain again. But lại has several uses in Vietnamese, including:

• repetition: làm lại = do again
• return/back: quay lại = return
• contrast/surprise in some contexts: sao lại... = why on earth... / why would...

So the meaning of lại depends on context. Here, the repetition meaning is the correct one.