Lǎo jiàoshòu jǐshí nián lái zīzībùjuàn de cóngshì yánjiū.
For decades the old professor has pursued his research tirelessly.
Tips
history
From 《尚书·君陈》: 「惟日孜孜，无敢逸豫」 - 'day after day, diligent; never daring idleness.' Reinforced by 《后汉书·鲁丕传》 and 《三国志·蜀书·向朗传》, where 孜孜不倦 describes lifelong scholars. Classical gold-standard for tireless study.
mistakes
孜 is zī, not zǐ. Tone sandhi in speech: 孜孜 (zī zī) + 不 becomes zī zī bú juàn because 倦 is fourth tone.
