以至于

这位老教授在古籍整理工作中投入了全部心血，以至于常常废寝忘食忘记了吃饭休息。

zhè wèi lǎo jiào shòu zài gǔ jí zhěng lǐ gōng zuò zhōng tóu rù le quán bù xīn xuè, yǐ zhì yú cháng cháng fèi qǐn wàng shí wàng jì le chī fàn xiū xī.

The old professor put all his efforts into the work of organizing ancient books, so much so that he often forgot to eat and sleep.