jīng / guò / duō / nián / de / kè / kǔ / liàn / xí / tā / de / shū / fǎ / jì / yì / yǐ / jīng / dá / dào / lú / huǒ / chún / qīng / de / jìng / jiè

经过多年的刻苦练习，他的书法技艺已经达到炉火纯青的境界。

After years of hard practice, his calligraphy skills have reached a level of perfection.