2 sentences for 退 (tuì — to cancel)

1. 我应该退掉这堂课的。

   wǒ yīng​gāi tuì diào zhè táng kè de.

   I should've dropped this class.

   Source: OpenSubtitles

2. 我第一个学期就退掉了一门课。

   wǒ dì​yī ge xué​qī jiù tuì diào le yī​mén kè.

   I dropped a class my first semester.

   Source: OpenSubtitles