yé / ye / yòng / shā / lòu / jì / shí / tí / xǐng / zì / jǐ / měi / gé / bàn / xiǎo / shí / xiū / xi / yí / cì

爷爷用沙漏计时，提醒自己每隔半小时休息一次。

Grandpa used an hourglass to time himself and remind himself to rest every half hour.