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to collect; to gather; to save; to accumulate; to pile up
洗濯物がたまってしまった。
The laundry has piled up.
お金がなかなかたまらなくて困る。
It's hard because I can't seem to save money.
疲れがたまると集中できなくなる。
When fatigue builds up, I can't concentrate.