Петя объяснил, что как раз в тот де

Петя объяснил, что как раз в тот день заболела его сестра и он должен был за ней ухаживать.

Results (English) 1:

Peter explained that the day his sister became ill and he had to look after her.

Results (English) 2:

Peter explained that just as the day his sister was ill and he had to take care of it.

Results (English) 3:

Petya explained that, as times in the day got sick his sister and he should have been taking care of it.