I can research you can research he can research we can research you can research they can research
Forma com V-ing
I can be researching you can be researching he can be researching we can be researching you can be researching they can be researching
Perfeito
I can have researched you can have researched he can have researched we can have researched you can have researched they can have researched
Perfeito com V-ing
I can have been researching you can have been researching he can have been researching we can have been researching you can have been researching they can have been researching
Negação
Forma simple
I cannot research you cannot research he cannot research we cannot research you cannot research they cannot research
Forma com V-ing
I cannot be researching you cannot be researching he cannot be researching we cannot be researching you cannot be researching they cannot be researching
Perfeito
I cannot have researched you cannot have researched he cannot have researched we cannot have researched you cannot have researched they cannot have researched
Perfeito com V-ing
I cannot have been researching you cannot have been researching he cannot have been researching we cannot have been researching you cannot have been researching they cannot have been researching
Forma interrogativa
Forma simple
can I research? can you research? can he research? can we research? can you research? can they research?
Forma com V-ing
can I be researching? can you be researching? can he be researching? can we be researching? can you be researching? can they be researching?
Perfeito
can I have researched? can you have researched? can he have researched? can we have researched? can you have researched? can they have researched?
Perfeito com V-ing
can I have been researching? can you have been researching? can he have been researching? can we have been researching? can you have been researching? can they have been researching?
Forma interro-Negação
Forma simple
can I not research? can you not research? can he not research? can we not research? can you not research? can they not research?
Forma com V-ing
can I not be researching? can you not be researching? can he not be researching? can we not be researching? can you not be researching? can they not be researching?
Perfeito
can I not have researched? can you not have researched? can he not have researched? can we not have researched? can you not have researched? can they not have researched?
Perfeito com V-ing
can I not have been researching? can you not have been researching? can he not have been researching? can we not have been researching? can you not have been researching? can they not have been researching?