Lan cứu con mèo.

Yes. This sentence uses the very common Vietnamese order Subject + Verb + Object:

• Lan = the subject
• cứu = the verb
• con mèo = the object

So in that sense, it works much like English: Lan rescued/saves the cat.

Con is a classifier, and here it is used with an animal noun.

In Vietnamese, classifiers are very common when talking about individual nouns. For animals, con is the normal classifier, so con mèo is the natural way to say cat when referring to an actual animal.

So:

• mèo = cat / cats in a general sense
• con mèo = a cat / the cat / one cat, depending on context

English does not have this kind of classifier system, so this often feels unusual at first.

Vietnamese usually does not use articles like English a/an and the.

That means con mèo can mean:

• a cat
• the cat

The exact meaning depends on context. If your lesson already gives the meaning as the cat, that interpretation is coming from context, not from a separate word equivalent to English the.

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

So cứu can be understood from context as something like:

• rescues
• rescued
• is rescuing
• will rescue

If you want to make the time clearer, Vietnamese often adds time or aspect markers, for example:

• Lan đã cứu con mèo. = Lan rescued the cat.
• Lan đang cứu con mèo. = Lan is rescuing the cat.
• Lan sẽ cứu con mèo. = Lan will rescue the cat.

You might hear nouns without classifiers in some situations, but for a normal sentence about rescuing an individual cat, con mèo is much more natural.

Compare:

• Lan cứu con mèo. = natural for Lan rescues/rescued a/the cat
• Lan cứu mèo. = more like Lan rescues cats or Lan saves cats in a general sense, or it may sound less natural if you mean one specific cat

So for learners, it is safest to use con with animal nouns like mèo when talking about one animal.

Not exactly.

• cứu means to rescue, save
• giúp means to help

So cứu is stronger. It usually suggests danger, trouble, or an urgent need.

For example:

• cứu con mèo = rescue/save the cat
• giúp con mèo = help the cat

If the cat is stuck somewhere or in danger, cứu is the better word.

A rough guide:

• Lan: level tone
• cứu: roughly like kyoo, with a rising tone
• con: level tone
• mèo: roughly meh-o said quickly as one syllable, with a falling tone

Tone-wise:

• cứu has the sắc tone, which rises
• mèo has the huyền tone, which falls

English approximations are never perfect, but the tones matter a lot in Vietnamese, so it is good to learn them early.

Here it is normally understood as singular: one cat.

Vietnamese nouns do not change form for singular vs. plural the way English nouns do. Instead, Vietnamese can add words if it wants to make plurality clear.

For example:

• con mèo = a cat / the cat / one cat
• những con mèo = cats
• các con mèo = the cats / cats

So in your sentence, con mèo is most naturally read as one cat.

Lan is very commonly a female given name in Vietnamese, so many learners will naturally interpret it that way.

However, grammatically, the sentence itself does not mark gender. Vietnamese often leaves gender unmarked unless a pronoun or some other word makes it explicit.

So while Lan is usually recognized as a woman’s name, the grammar of the sentence is not doing anything special to show gender.

To make it negative, add không before the verb:

• Lan không cứu con mèo. = Lan did not rescue / does not rescue the cat.

A common yes/no question pattern is có ... không:

• Lan có cứu con mèo không? = Did/Does Lan rescue the cat?

You may also hear shorter spoken forms such as:

• Lan cứu con mèo à?

That sounds more like checking, reacting, or asking with surprise, depending on tone and context.