Моя сестра торопится и чистит зубы той же щёткой и той же пастой.

The ending -ся (or -сь) marks a reflexive verb in Russian.

• торопиться = “to be in a hurry, to hurry (oneself)”

  • Она торопится. – She is in a hurry / She’s hurrying.

• торопить = “to hurry / rush someone else, to urge someone on”

  • Она торопит сестру. – She is hurrying (urging) her sister.

So in your sentence, торопится describes your sister’s own state (“is in a hurry”), not that she is hurrying someone else.

Formally:

• infinitive: торопиться
• он/она/оно: торопится
• я: тороплюсь
• ты: торопишься
• мы: торопимся
• вы: торопитесь
• они: торопятся

Yes, торопится is present tense, 3rd person singular.

Russian has only one present tense form, and it covers both:

• English simple present: she hurries
• English present continuous: she is hurrying / she is in a hurry

So:

• Она торопится. can mean both She hurries and She is in a hurry / She’s hurrying depending on context.

There is no separate grammatical form for “is hurrying”; Russian uses the same present tense and lets context show whether it’s a general habit or something happening now.

This is about case.

• моя сестра is in the nominative case (subject of the sentence).

  • Кто торопится? – моя сестра. (Who is in a hurry? My sister.)

• мою сестру is accusative case, used mainly for direct objects:

  • Я вижу мою сестру. – I see my sister.

In the sentence Моя сестра торопится и чистит зубы…, my sister is the subject doing the actions, so Russian uses the nominative form моя сестра, not мою сестру.

Russian often omits possessive pronouns (my, your, his, her, etc.) when it’s obvious whose thing it is, especially with body parts and close relatives.

• Она чистит зубы. – literally She cleans teeth, but naturally understood as She brushes *her teeth.*
• Он мыл руки. – He washed *his hands.*
• Она закрыла глаза. – She closed *her eyes.*

You only say её зубы (“her teeth”) if you need to contrast or clarify, e.g.:

• Она чистит свои зубы, а не её зубы.
  She is brushing her own teeth, not her (another woman’s) teeth.

In the normal situation, чистит зубы is fully enough to mean “brushes her teeth.”

Russian normally uses the plural with this expression:

• чистить зубы – to brush (one’s) teeth

Just like in English, we usually mean all or several teeth, so the plural is natural.

You can say чистит зуб, but it would sound like:

• “is cleaning a single tooth” – e.g. at the dentist, focusing deliberately on one tooth. In everyday speech about normal toothbrushing, чистит зуб sounds strange and incomplete.

So:

• Habitual / normal action: Она каждый день чистит зубы.
• Very specific, unusual context: Стоматолог тщательно чистит этот зуб.

Russian doesn’t use a special verb meaning “to brush (with a brush)” for teeth. It uses the general verb чистить, which means:

• чистить = “to clean, to make clean, to scrub / brush clean”

Examples:

• чистить зубы – to brush teeth
• чистить ботинки – to clean/polish shoes
• чистить картошку – to peel potatoes
• чистить ковёр – to clean a carpet

The noun щётка is “a brush”, but there is no everyday verb like щётить for “to brush” with a brush. You just say чистить + what you’re cleaning.

• тот / та / то / те = “that” (demonstrative pronoun)
• той is one of its forms (feminine in several cases).
• же here is a little particle that emphasizes identity: “the same (one)”.

So:

• той щёткой – with that toothbrush (a specific one already mentioned or pointed to)
• той же щёткой – with the same toothbrush (the identical one you’ve already mentioned or someone else used)

In your sentence:

• той же щёткой и той же пастой = “with the same toothbrush and the same toothpaste (as someone else, or as before).”

Don’t confuse же here with тоже (“also, too”).
той же = “the same (one)”
тоже = “also”

They are in the instrumental case.

The instrumental case often answers the question чем? – with what? by what means?

Here:

• чистит (чем?) – той же щёткой и той же пастой
• she cleans (with what?) – with the same toothbrush and the same toothpaste.

This is the standard pattern:

• писать ручкой – to write with a pen
• есть ложкой – to eat with a spoon
• резать ножом – to cut with a knife
• мыть тряпкой – to wash with a rag
• чистить зубы щёткой – to brush teeth with a brush

So щёткой and пастой must be in the instrumental.

Both щётка and паста are feminine nouns in -а.

In the singular instrumental case, most such nouns take the ending -ой (or sometimes -ей):

• щётка → щёткой
• паста → пастой
• рука → рукой – hand
• книга → книгой – book
• машина → машиной – car

After certain consonants or with certain stress patterns, you may see -ей instead:

• девушка → девушкой
• тетрадь (f.) → тетрадью (here it’s a different pattern, since it ends in a soft consonant)

In your sentence:

• той же щёткой = with the same toothbrush
• той же пастой = with the same toothpaste

The -ой ending is exactly what marks these as instrumental singular feminine.

Grammatically, both are possible:

1. той же щёткой и той же пастой

   • Fully explicit: both the toothbrush and the toothpaste are “the same” ones.

2. той же щёткой и пастой

   • Still understandable. Usually listeners will interpret that both are the same as previously mentioned (though grammatically only щёткой is explicitly marked as “the same”).

Native speakers often repeat той же when they want to put equal emphasis on both nouns, especially in more careful or written speech.

In informal spoken Russian, you might hear:

• той же щёткой и пастой
• той же щёткой и той же пастой both are acceptable; the repeated version just sounds a bit clearer and more emphatic.

чистит is imperfective aspect, present tense.

• чистить (impf.) – focuses on process, repeated action, or habit
• почистить (pf.) – focuses on the completed result of one action

Your original sentence:

• Моя сестра торопится и чистит зубы той же щёткой и той же пастой.
  – My sister is in a hurry and (is) brushing her teeth with the same toothbrush and the same toothpaste.
  This can describe what she’s doing now or something she typically does when she’s in a hurry.

If you said:

• Моя сестра торопится и почистит зубы той же щёткой и той же пастой.
  This sounds like: My sister is in a hurry and *will (go and) brush her teeth with the same toothbrush and the same toothpaste.
  – *почистит here is future, perfective, implying a single, completed action in the future.

Past tense examples:

• Моя сестра торопилась и чистила зубы…
  – She was in a hurry and (was) brushing / used to brush her teeth…
• Моя сестра торопилась и почистила зубы…
  – She was in a hurry and (she did) brush her teeth (and finished doing it).

So the choice чистит vs. почистит mainly affects:

• time (present vs. future/past with result)
• focus on process vs. completed result.

Yes, you can say:

• Моя сестра спешит и чистит зубы той же щёткой и той же пастой.

Both торопиться and спешить can mean something like “to be in a hurry / to hurry,” but there are nuances:

• торопиться = to be in a hurry, to feel pressed for time

  • More about the state of being in a rush.
  • Я тороплюсь. – I’m in a hurry.

• спешить = to hurry, to rush (often somewhere)

  • Slightly more about moving quickly or hurrying toward a goal.
  • Я спешу на работу. – I’m hurrying to work.

In your sentence, both are natural.
торопится subtly highlights “she’s in a hurry (so she does this),”
спешит slightly leans toward “she’s rushing (somewhere) and meanwhile she does this.”
The difference is small; both are acceptable.

Russian does not put a comma between two verbs that share the same subject and are simply joined by и:

• Моя сестра торопится и чистит зубы…

Here:

• subject: Моя сестра
• predicates: торопится and чистит

This is a compound predicate with one subject and two verbs, so no comma is needed.

You would expect a comma with и if, for example:

• there were different subjects, or

• it were joining independent clauses with their own subjects:

• Моя сестра торопится, и брат злится.
  My sister is in a hurry, and my brother is angry.
  (Two separate clauses, two subjects: сестра and брат.)

In your sentence, one subject + two verbs = no comma before и.