sentakumono ga tamatta node, harete iru uchi ni aratte hoshimasu.

Because the laundry has piled up, I’ll wash it and hang it out while it’s still sunny.

Breakdown of sentakumono ga tamatta node, harete iru uchi ni aratte hoshimasu.

• が: subject particle
• ので: reason particle
• 〜て いる: progressive form
• 〜て: connective form

Questions & Answers about sentakumono ga tamatta node, harete iru uchi ni aratte hoshimasu.

What does 洗濯物 mean here?

洗濯物 literally means washing / laundry items. In everyday use, it usually means laundry as a group.

In this sentence, it refers to the clothes or other things that need to be washed. Depending on context, 洗濯物 can sometimes mean:

• dirty laundry waiting to be washed
• washed laundry that is being dried or folded

Here, because of たまった and then 洗って干します, it means laundry that has piled up and needs to be washed.

Why is が used after 洗濯物 instead of は?

洗濯物がたまった means the laundry piled up / has accumulated.

Here, が marks 洗濯物 as the thing that underwent the change of state. The laundry is what became piled up.

This is natural because たまる is an intransitive verb:

• たまる = to accumulate, pile up
• ためる = to accumulate something, to save something up

So:

• 洗濯物がたまった = The laundry piled up.
• 洗濯物をためた = I accumulated the laundry.
  This second version is grammatically possible, but it sounds less natural in this context.

Using は instead would give more of a topic nuance:

• 洗濯物はたまったので... = As for the laundry, since it piled up...

That is possible, but が is the more neutral and direct choice here.

Why is たまった in the past tense?