Помогите исправить ошибки! Заранее благодарю!!)))

1.need->needed 2.this->that 3.don't->not 4.is->was 5.has->has 6.will->would 7.yesterday->the previous day 8.lost->had lost 9.could Tom->Tom could 10.had the train->the train had 11.had I->I had 12.would Olga->Olga would