2 sentences for 以至于 (yǐ​zhì​yú)

1. 他工作太忙了，以至于忘了吃饭。

   tā gōng​zuò tài máng le, yǐ​zhì​yú wàng le chī​fàn.

   He was so busy with work that he forgot to eat.

   Source: Dong Chinese Dictionary

2. 他的书房里到处是书，桌子上、椅子上，以至于地板上。

   tā de shū​fáng lǐ dào​chù shì shū, zhuō​zi shàng, yǐ​zi shàng, yǐ​zhì​yú dì​bǎn shàng.

   There were books everywhere in his study: on the desk, on the chairs, and even on the floor.

   Source: Dong Chinese Dictionary