Respostas
1. b
2. a
3. b
4. a
5. a
6. a
7. b
8. b
9. b
10. b
11. a
12. b
O present perfect, na afirmativa, é formado por sujeito + auxiliar have + verbo no past participle
Quando o sujeito for I, you, we ou they, usa-se have. Quando for she, he ou it, usa-se has.
Na negativa, basta adicionar not após o auxiliar, que pode ser contraído como hasn't ou haven't.
Com isso, temos que as orações de 1 a 6 ficam da seguinte maneira na forma negativa:
1. My sister hasn't eaten my cakes.
2. The children haven't lost their passports.
3. You friend hasn't been happy all day.
4. I haven't travelled overseas.
5. We haven't cut our hair today.
6. I haven't taken a shower.
Na interrogativa, coloca-se o auxiliar antes do sujeito, ficando: auxiliar + sujeito + verbo no past participle.
Portanto, as orações de 7 a 12 ficam:
7. Has my husband forgotten my bday?
8. Has anyone taken my pen?
9. Has the train left the station?
10. Has it rained a lot this month?
11. Have I looked all morning for my keys?
12. Has that woman worked at the museum?