Bié rēng le, shuōbudìng yǐhòu néng pài shàng yòngchǎng.
Don't throw it away — it might come in handy later.
Tips
usage
用场 almost always appears in the phrase 派上用场 (pài shàng yòngchǎng, to come in handy / to put to use). It's rarely used on its own outside this fixed expression.
