The 一 … 就 pattern (yī … jiù) is super common in Chinese grammar and is used to say that two actions happened in quick succession. For example: "as soon as I got home, I called you", or "once I finished class, I began revising". In today's example, it's a bit of a lovers tiff, where the girlfriend is upset that the boyfriend didn't call her. However, he claims that as soon as he finished work, he called right away. You can also check out this Elementary lesson to see the yi...jiu pattern in use. Click here Photo by Alejandro Pinto