Respostas
1- I bought fruit at the farmer's market (afirmativa no passado)
2- her make up is not that pretty (negativa no presente)
3- I'm eating spaghetti now (afirmativa no presente contínuo = ing sempre é usado com verb to be)
4- Did you get a certificate last year? (pergunta no passado = verbo fica normal, só o did é passado)
5- Is the guest taking a shower? (pergunta no presente contínuo = sempre é usado ING com VERB TO BE)
6- doesn't katie have to go home? (pergunta negativa no presente. katie = she = doesn't = verbo fica sem S)
7- They aren't hanging out with their friends (negativo no presente contínuo)
8- the lady is eating at the restaurant (afirmativo no presente contínuo)
9- my cell phone wasn't in my house last night (negativo no passado)
Espero que tenha ajudado! ;)