波動；需求、成本或運費在一段時間內不規則變化
Freight rates fluctuate significantly during peak shipping seasons.
運費在出貨旺季期間波動幅度顯著加大。
想把「fluctuate」記進長期記憶？
登入後用科學排程（FSRS）複習，還有連續天數與徽章等你解鎖。