Meine Schwester sucht eine Wäscheklammer, weil sie das neue Waschpulver draußen stehen gelassen hat.

Because weil means because and introduces a subordinate clause. In German, subordinate clauses usually send the conjugated verb to the end.

So:

• Meine Schwester sucht eine Wäscheklammer = main clause
• weil sie das neue Waschpulver draußen stehen gelassen hat = subordinate clause

That final hat is the conjugated verb of the subordinate clause.

This is the Perfekt tense, which is very common in spoken and everyday German for talking about past events.

The basic verb is stehen lassen, which means something like:

• to leave standing
• more naturally here: to leave out / to leave somewhere

In the Perfekt, it becomes:

• hat stehen gelassen

So the clause means that she has left the new washing powder outside.

It comes from the separable verb stehen lassen.

Breakdown:

• stehen = to stand
• lassen = to let / to leave

Together, etwas stehen lassen often means to leave something where it is, especially when you forgot to put it away.

In the perfect tense:

• lassen becomes the past participle gelassen
• stehen stays as an infinitive

So:

• sie hat das Waschpulver draußen stehen gelassen

This is a normal pattern with lassen.

Because Wäscheklammer is a feminine noun: die Wäscheklammer.

After suchen (to look for), the thing being looked for is the direct object, so it goes in the accusative case.

For a feminine noun:

• nominative: eine Wäscheklammer
• accusative: eine Wäscheklammer

The form happens to stay the same, so you do not see a change here.

Because Waschpulver is neuter: das Waschpulver.

It is also the direct object of stehen lassen, so it is in the accusative.

For a neuter noun:

• nominative: das neue Waschpulver
• accusative: das neue Waschpulver

Again, the form does not change, so nominative and accusative look the same here.

Draußen means outside.

It is an adverb, and here it tells you where the washing powder was left.

So:

• das neue Waschpulver draußen stehen gelassen = left the new washing powder outside

Its position is natural in German: it appears before the verb group at the end.

In this sentence, yes, that is the natural meaning.

Grammatically, sie could in theory refer to a feminine noun, and both Schwester and Wäscheklammer are feminine. But semantically, only the sister makes sense as the person who left the washing powder outside.

So learners should know:

• German pronouns can sometimes be grammatically ambiguous
• the intended meaning is often clear from context and logic

Here, sie clearly refers to meine Schwester.

Because meine is a possessive determiner and already fills the role that an article would normally fill.

So German says:

• meine Schwester = my sister

not:

• die meine Schwester in this kind of sentence

Possessive words like mein, dein, sein, ihr, unser work similarly to a/an/the in terms of noun phrase structure.

In a subordinate clause with weil, the verbal material clusters at the end.

Here the final verb group is:

• stehen gelassen hat

with draußen placed before it.

That order reflects:

1. the adverb draußen
2. the infinitive part stehen
3. the participle gelassen
4. the conjugated auxiliary hat

This may feel very different from English, but it is a normal German end-of-clause verb structure.

Yes. German allows the subordinate clause to come first or second.

For example:

• Meine Schwester sucht eine Wäscheklammer, weil sie das neue Waschpulver draußen stehen gelassen hat.
• Weil sie das neue Waschpulver draußen stehen gelassen hat, sucht meine Schwester eine Wäscheklammer.

Both mean the same thing. If the weil clause comes first, the main clause must still follow normal German word order, with the verb in second position:

• ..., sucht meine Schwester ...

not

• ..., meine Schwester sucht ...

Both are possible, depending on context.

• suchen literally means to search for / to look for
• In natural English here, is looking for is often the best translation

So:

• Meine Schwester sucht eine Wäscheklammer can mean
• My sister is looking for a clothespin or
• My sister is searching for a clothespin

The German present tense often covers both simple present and present progressive ideas.

Weil is one of the most common everyday ways to say because in German.

Another option is denn:

• Meine Schwester sucht eine Wäscheklammer, denn sie hat das neue Waschpulver draußen stehen gelassen.

The difference is grammatical:

• weil introduces a subordinate clause, so the verb goes to the end
• denn connects two main clauses, so normal word order stays

Compare:

• ..., weil sie ... stehen gelassen hat
• ..., denn sie hat ... stehen gelassen

Both are correct, but weil is especially common in everyday speech and writing.