I have studied chemistry in the UNAM for 4 year
she has played golf
he has worked at school since college
she has been a nurse for 5 years
i have been a doctor since i was 34
we have been actors for 12 years
NEGATIVE
i havent´t met another good doctor in 5 years
they havent´t been good footballers since college
i haven´t seen a better actor in 16 years
i haven´t seen thist dentist for 3 years
i haven´t met a good builder in 4 years
INTERROGATIVE
have you worked as actor for 13 years?
have they worked as voice over artist since college?
have you worked as teacher for 14 years?
have you are a soccer player since college?
have they been artist for 5 years?
