Respostas
7. a) wasn't studying / was watching
b) was painting
c) were / playing
d) was wearing
e) was / fishing
f) weren't working / were having
8. a) She was singing.
b) I was watching TV.
c) He was crossing the street.
d) They were sleeping.
e) He was walking in the forest.
f) He was taking a shower.
9. a) No, she wasn't.
b) They were not.
c) Yes, but I was talking with the teacher.
d) Yes, it was a little bit.
e) No, they weren't, but they started after.
f) I was having classes an hour ago.
* Tome cuidado que a 9 é bem pessoal, então dependendo das situações, elas demandam que haja um conhecimento sobre o que você estava fazendo e seus colegas de classe e tudo mais. Tomei a liberdade para criar algumas situações que fazem sentido, então se não tem nada em específico, use-as sem problema.