Ответ:

1. By eight o'clock yesterday, I had done my homework

and at eight I was playing the piano.

- Вчера к восьми часам я сделал домашнее задание,

а в восемь я уже играл на пианино.

2. By six o'clock father had come home and at six he was having dinner.

- К шести часам отец вернулся домой, а в шесть он ужинал.

Объяснение:

1) had done - Past Perfect

  was playing - Past Continuous

2) had come - Past Perfect

    was having - Past Continuous