동사 + -기 시작하다
Use -기 시작하다 after a verb stem to say that an action or change begins. In the story, "구름이 몰려오기 시작했다" means "the clouds began to roll in," and "호수는 반짝이기 시작했다" means "the lake began to sparkle." You can reuse this pattern for many actions, such as "비가 내리기 시작했다" = "It started to rain."
비가 내리기 시작했다.
It started to rain.
