3 sentences

1. 他最近忙得不可开交。

   tā zuì​jìn máng de bù​kě​kāi​jiāo.

   He's been incredibly busy lately.

   Source: Dong Chinese Dictionary

2. 战争期间，我忙得不可开交。

   zhàn​zhēng qī​jiān, wǒ máng de bù​kě​kāi​jiāo.

   I was extremely busy during the war.

   Source: OpenSubtitles

3. 工作已经忙到了不可开交的地步。

   gōng​zuò yǐ​jīng máng dào le bù​kě​kāi​jiāo de dì​bù.

   Work has become so busy that it's reached an overwhelming level.

   Source: Dong Chinese Dictionary