“直到那时”常见的英文表达有 “until then” 或 “not until then”(后者带有“直到那时才……”的强调意味)。
Until then, we'll just have to wait patiently.(直到那时,我们只能耐心等待。)
Not until then did I realize the importance of this opportunity.(直到那时,我才意识到这个机会的重要性 。)