Respostas

2014-03-31T16:06:23-03:00
They aren't (ou are not) good students.
2014-03-31T16:08:23-03:00
Depende, se for no presente  diz-se They are not (aren't) good students
se for no passado they were not (weren't) good students
ou no futuro they will not (won't) good students