comfort zone
noun [ C ] uk/ˈkʌm.fət ˌzəʊn/ us/ˈkʌm.fɚt ˌzoʊn/
舒适区（指让人感到舒服而不费力气的状况）
a situation in which you feel comfortable and in which your ability and determination are not being tested
Rock climbing pushes many people beyond their comfort zones. 攀岩运动对许多人来说是对能力与毅力的考验。