Дочка долго смотрела, как бабочка садится на цветок, а пчела летит к другому.

Both mean daughter, but дочка is the more affectionate, everyday form. It often sounds warmer and more natural in ordinary speech.

Grammatically, дочка here is in the nominative singular because it is the subject of the sentence.

Because the subject, дочка, is feminine singular.

In the Russian past tense, the verb agrees with the subject in gender and number:

• смотрел = masculine
• смотрела = feminine
• смотрело = neuter
• смотрели = plural

So with дочка, you need смотрела.

Here как introduces what the girl was watching. After verbs of seeing, hearing, watching, noticing, and so on, как often means something like:

• how
• the way
• as

So смотрела, как... means watched how... / watched as...

It is not a question word here.

This is very common in Russian after verbs of perception like смотреть, видеть, слышать.

Russian often uses the present tense in the subordinate clause to show the action as unfolding before the observer’s eyes:

• смотрела, как бабочка садится...
• watched as the butterfly was landing...

It makes the scene feel more immediate and vivid.

English usually prefers a past form here, but Russian is comfortable using the present in this kind of description.

Because the verb is садиться, which means to sit down or, for things like insects and birds, to land / settle onto something.

So:

• бабочка садится на цветок = the butterfly is landing on the flower

Without -ся, you get a different verb:

• садить usually means to plant or sometimes to seat someone

So садится is the correct form for the butterfly itself moving into place.

Because the sentence focuses on the actions in progress, as something the girl is watching.

• садится shows the butterfly in the process of landing
• летит shows the bee in the process of flying

If you used completed forms such as села or полетела, the meaning would shift more toward finished, single events.

So the imperfective forms fit the idea of a scene being observed over time.

Because на can take different cases depending on whether you mean movement to a place or location at a place.

• на + accusative = movement onto / toward a surface
• на + prepositional = being on a surface

So:

• садится на цветок = is landing onto the flower
• сидит на цветке = is sitting on the flower

Here the butterfly is moving onto the flower, so цветок is in the accusative.

The noun is understood from context and left out.

Full version:

• к другому цветку = to another flower

Since цветок was just mentioned, Russian can omit it and simply say:

• к другому

This means something like to another one.

Also, к requires the dative case, so другому is dative singular, agreeing with the omitted цветку.

Because а often sets two things side by side with a slight contrast or comparison.

Here the sentence is presenting two simultaneous scenes:

• the butterfly is landing on one flower,
• while the bee is flying to another.

So а feels natural because it means something like:

• while
• whereas
• and meanwhile

Using и would just add information. Using а gives a clearer contrast between what the butterfly is doing and what the bee is doing.

Because Russian punctuation marks clause boundaries very consistently.

• The comma before как separates the main clause from the subordinate clause:

  • Дочка долго смотрела, как...

• The comma before а separates two coordinated clauses:

  • ..., а пчела летит...

So the commas reflect the sentence structure, not just pauses in speech.