Meine Schwester gießt die Blumen mit der Gießkanne, während ich auf dem Balkon sitze.

Because Schwester is a feminine noun.

The possessive mein- changes its ending depending on gender, case, and number:

• mein Bruder = my brother
• meine Schwester = my sister

Here, Schwester is the subject of the sentence, so it is in the nominative case, feminine singular, which gives meine.

Gießt is the third-person singular form of gießen, which means to water or to pour.

Since the subject is meine Schwester = my sister, German uses the she form:

• ich gieße
• du gießt
• er/sie/es gießt

So Meine Schwester gießt ... means My sister waters ...

Also, the letter ß is pronounced like ss.

Die Blumen is the direct object, the thing being watered.

The verb gießen takes an accusative object, so Blumen is in the accusative case.

Here, Blumen is plural. In the plural, the definite article is often:

• nominative plural: die
• accusative plural: die

So although it is accusative here, it still appears as die Blumen.

Because mit always takes the dative case.

• mit = with
• Gießkanne = watering can

Since Gießkanne is feminine, its dative singular article is der:

• nominative: die Gießkanne
• dative: der Gießkanne

So:

• mit der Gießkanne = with the watering can

It tells you what tool is being used.

So the phrase means that the sister is watering the flowers using the watering can.

It is an instrumental use of mit:

• mit der Gabel essen = to eat with a fork
• mit dem Bus fahren = to go by bus
• mit der Gießkanne gießen = to water with a watering can

Because während introduces a subordinate clause here.

German normally uses a comma before subordinate clauses:

• ..., während ich auf dem Balkon sitze.

This is similar to English while I am sitting on the balcony, although German is stricter about the comma.

Because während is a subordinating conjunction, and in German subordinate clauses the conjugated verb usually goes to the end.

Main clause:

• Meine Schwester gießt die Blumen ...

Subordinate clause:

• während ich auf dem Balkon sitze

That final verb position is one of the most important word-order patterns in German.

Because this sentence describes location, not movement toward a destination.

German uses two-way prepositions like auf with:

• dative for location: where?
• accusative for direction/movement: where to?

Here, the speaker is already sitting there:

• auf dem Balkon sitzen = to sit on the balcony

If there were movement onto the balcony, you would use accusative:

• Ich gehe auf den Balkon. = I go onto the balcony.

It is in the present tense.

• gießt = waters / is watering
• sitze = sit / am sitting

German often uses the simple present where English may prefer either:

• My sister waters the flowers ...
• My sister is watering the flowers ...

Both can match the German present, depending on context.

Yes.

In this sentence, während is a conjunction meaning while:

• während ich auf dem Balkon sitze = while I am sitting on the balcony

But während can also be a preposition meaning during:

• während des Sommers = during the summer

So learners should notice the structure:

• während + clause = while
• während + noun phrase = during

No, not here.

German usually requires an explicit subject in a normal sentence clause, unlike some languages where the verb ending alone can be enough.

So you need:

• während ich auf dem Balkon sitze

not just

• während auf dem Balkon sitze

The pronoun ich is necessary because it tells us who is sitting.

No. Gießen has a broader meaning.

It can mean:

• to water plants
• to pour a liquid

Examples:

• Sie gießt die Blumen. = She waters the flowers.
• Er gießt Wasser ins Glas. = He pours water into the glass.

So in this sentence, the meaning is specifically to water because the object is die Blumen.

Yes. Gießkanne is a compound noun, which is very common in German.

It is made of:

• gieß- from gießen = to pour/water
• Kanne = can / jug

So Gießkanne literally means something like pouring can, which is why it means watering can.

Recognizing compounds can make German vocabulary much easier to learn.