मैं दरवाज़े पर ताला लगाती हूँ।

लगाती is the feminine singular habitual form of the verb लगाना.

So this sentence suggests that the speaker is female.

• मैं ... लगाती हूँ = I ... lock / I put ...
• If the speaker were male, it would be: मैं दरवाज़े पर ताला लगाता हूँ।

In Hindi, the verb often shows the gender of the speaker in sentences like this.

हूँ is the first-person singular form of होना (to be), used as an auxiliary here.

In the pattern:

• लगाती हूँ
• लगाता हूँ

the main verb form (लगाती / लगाता) combines with हूँ to make the habitual present.

So:

• मैं ताला लगाती हूँ = I lock / I do lock / I usually lock

It is not the same as the English continuous I am locking.

Normally, मैं दरवाज़े पर tाला लगाती हूँ means I lock the door, I put a lock on the door, or I usually lock the door.

It is a habitual/simple present meaning, not a present continuous one.

If you want I am locking the door, Hindi would usually say:

• मैं दरवाज़े पर ताला लगा रही हूँ। (female speaker)
• मैं दरवाज़े पर ताला लगा रहा हूँ। (male speaker)

So the sentence you were given is more like a general action or habit than something happening right now.

Because पर is a postposition, and nouns before postpositions usually go into the oblique form.

So:

• direct form: दरवाज़ा
• oblique form: दरवाज़े

That is why Hindi says:

• दरवाज़े पर = on the door / at the door

This is a very common pattern:

• घर → घर में
• लड़का → लड़के को
• दरवाज़ा → दरवाज़े पर

A learner often mistakes दरवाज़े for plural, but here it can be singular oblique.

पर usually means on, at, or sometimes onto, depending on context.

In this sentence, दरवाज़े पर literally means on the door.

So the expression is literally something like:

• I put a lock on the door

That is why the full sentence is understood as I lock the door.

Literally, ताला लगाना means to put/apply a lock.

It is a very common Hindi expression for to lock.

So Hindi often expresses the idea differently from English:

• English: lock the door
• Hindi: put a lock on the door

This kind of expression is very natural in Hindi. You should learn ताला लगाना as a set phrase.

Because the sentence does not need को here.

The phrase is:

• दरवाज़े पर = on the door
• ताला = lock

So Hindi is not treating door as a direct object in the same way English does in lock the door. Instead, it is expressing the action as putting a lock on the door.

That is why you get:

• दरवाज़े पर ताला लगाना

and not something like:

• दरवाज़े को ताला लगाना in this normal expression

So this is partly a matter of idiom, not just grammar.

Here it is singular.

This is a very common source of confusion because दरवाज़े can also be a plural form in other contexts. But in this sentence, it is the singular oblique form of दरवाज़ा, used before the postposition पर.

So:

• दरवाज़ा = door
• दरवाज़े पर = on the door

If you were talking about doors in a different grammatical environment, दरवाज़े could also be plural. Context tells you which one it is.

Yes, Hindi word order is somewhat flexible, although some orders sound more natural than others.

The most neutral version is:

• मैं दरवाज़े पर ताला लगाती हूँ।

You may also hear:

• मैं ताला दरवाज़े पर लगाती हूँ।

Both are understandable, but the original order sounds very natural and standard.

In Hindi, the verb usually comes near the end, and other elements can move for emphasis.

The dictionary form is लगाना.

Important related forms:

• लगाना = to put, attach, apply, set, impose, lock, etc. depending on context
• लगाती = feminine singular habitual
• लगाता = masculine singular habitual
• लगाई = put/applied (in some past constructions)
• लगा रही = putting / locking (feminine progressive)

This verb is very common and has many meanings, so context matters a lot.

A male speaker would say:

• मैं दरवाज़े पर ताला लगाता हूँ।

The only change is:

• लगाती → लगाता

That is because the habitual verb form agrees with the gender of the speaker when the subject is मैं in this kind of sentence.

They are related, but not the same.

• दरवाज़ा बंद करती हूँ = I close the door
• दरवाज़े पर ताला लगाती हूँ = I lock the door / put a lock on the door

A door can be closed without being locked.

So ताला लगाना is more specific than बंद करना.

No, but it is one of the most common words.

You may also see दरवाजा without the dot under ज़ in informal writing. The pronunciation difference is often minor in everyday speech, and many people do not strictly distinguish ज़ from ज.

So you might encounter:

• दरवाज़ा
• दरवाजा

Both are commonly understood as door.

A very literal breakdown would be:

• मैं = I
• दरवाज़े पर = on the door
• ताला = lock
• लगाती हूँ = put / apply (habitually, feminine speaker)

So word-for-word, it is roughly:

• I put a lock on the door

But natural English is usually:

• I lock the door

This is a good example of how Hindi and English often express the same idea in different ways.