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to swell; to rise; to bulge; to be piled up
to rouse; to get excited
パーティーは深夜まで盛り上がった。
The party was lively until late at night.
試合が盛り上がって観客が熱狂した。
The game became exciting and the audience went wild.
場が盛り上がってきた。
The atmosphere has been heating up.