Explanation: This sentence is describing two actions that happened in the past in a specific order. First, the window was broken, and then the children came. Therefore, the correct verb tense to use is the past perfect tense "had broken" for the window, and "had come" for the children.
a) had broken/ had come
Explanation: This sentence is describing two actions that happened in the past in a specific order. First, the window was broken, and then the children came. Therefore, the correct verb tense to use is the past perfect tense "had broken" for the window, and "had come" for the children.