"Give me 15 minutes. I want to get changed."

Translation: 给我十五分钟，我想换衣服。

[mangaissei]

there is no sentence "clothes", why do i need to translate "衣服"？

[Kal-in]

Because you can't just 換 without an object.

[deactivated user]

Why is 我 required a secind time in the sentence when a second personal pronoun has not been used/required in other similar exercises?

[varigby]

Because people often say it that way.