Ответ:
1.1) I helped...
1.2) We walked...
1.3) They washed...
1.4) We watched...
1.5) Students worked...
2.1) She didn't help in the garden
2.2) Did she help in the garden?
3.1) Lisa didn't use her old dictionary
3.2) Did Lisa use her old dictionary?
4.1) We didn't started school at half-past eight
4.2) Did we started school at halp-past eight?
5.1) Paul and Cathy didn't tidy their room
5.2) Did Paul and Cathy tidy their room?