Subject + 挥 + 了 + 挥 + Object
The verb 挥 (huī) means "to wave" or "to swing" and is used to describe a waving motion, such as waving one's hand. It often appears in the reduplicated pattern 挥了挥 to indicate a brief waving action. A common collocation is 挥手, meaning "to wave one's hand."
她朝我挥了挥手,然后转身走了。
tā cháo wǒ huī le huī shǒu, ránhòu zhuǎnshēn zǒu le.
She waved at me, then turned around and left.
他站在窗边,挥手跟我们告别。
tā zhàn zài chuāng biān, huīshǒu gēn wǒmen gàobié.
He stood by the window and waved goodbye to us.
教练挥了挥旗子,比赛正式开始。
jiàoliàn huī le huī qízi, bǐsài zhèngshì kāishǐ.
The coach waved the flag, and the competition officially began.