huā / yàng / huá / bīng / yùn / dòng / yuán / tōng / guò / shōu / jǐn / shǒu / bì / lái / gǎi / biàn / zì / jǐ / de / jiǎo / dòng / liàng

花样滑冰运动员通过收紧手臂来改变自己的角动量。

Figure skaters change their angular momentum by pulling their arms in.