My little sister__half an hour ago

It seems like you are looking to complete the sentence. Here are a few options for what you could say:

1. "My little sister left for school half an hour ago."
2. "My little sister finished her homework half an hour ago."
3. "My little sister was playing outside half an hour ago."
4. "My little sister called me on the phone half an hour ago."
5. "My little sister ate lunch half an hour ago."

Feel free to choose one or modify it as needed!