Definition
To maintain a vertical position in the water by making continuous up-and-down movements with the arms and legs.
（水中）踩水
In the deep end, he could only tread water until the lifeguard arrived.
在深水區，他只能踩水直到救生員到達。
She felt exhausted treading water, but she knew she had to keep going.
她感到踩水很累，但她知道必須繼續下去。
They had to tread water for over an hour while waiting for rescue.
他們不得不踩水超過一個小時，等待救援。