English verb conjugation
CAN UNDERSTAND

Irregular verb: understand - understood - understood

Affirmation

Simple form	V-ing form
I can understand you can understand he can understand we can understand you can understand they can understand	I can be understanding you can be understanding he can be understanding we can be understanding you can be understanding they can be understanding
Perfect	V-ing perfect
I can have understood you can have understood he can have understood we can have understood you can have understood they can have understood	I can have been understanding you can have been understanding he can have been understanding we can have been understanding you can have been understanding they can have been understanding

Negation

Simple form	V-ing form
I cannot understand you cannot understand he cannot understand we cannot understand you cannot understand they cannot understand	I cannot be understanding you cannot be understanding he cannot be understanding we cannot be understanding you cannot be understanding they cannot be understanding
Perfect	V-ing perfect
I cannot have understood you cannot have understood he cannot have understood we cannot have understood you cannot have understood they cannot have understood	I cannot have been understanding you cannot have been understanding he cannot have been understanding we cannot have been understanding you cannot have been understanding they cannot have been understanding

Interrogative form

Simple form	V-ing form
can I understand? can you understand? can he understand? can we understand? can you understand? can they understand?	can I be understanding? can you be understanding? can he be understanding? can we be understanding? can you be understanding? can they be understanding?
Perfect	V-ing perfect
can I have understood? can you have understood? can he have understood? can we have understood? can you have understood? can they have understood?	can I have been understanding? can you have been understanding? can he have been understanding? can we have been understanding? can you have been understanding? can they have been understanding?

Interro-negative form

Simple form	V-ing form
can I not understand? can you not understand? can he not understand? can we not understand? can you not understand? can they not understand?	can I not be understanding? can you not be understanding? can he not be understanding? can we not be understanding? can you not be understanding? can they not be understanding?
Perfect	V-ing perfect
can I not have understood? can you not have understood? can he not have understood? can we not have understood? can you not have understood? can they not have understood?	can I not have been understanding? can you not have been understanding? can he not have been understanding? can we not have been understanding? can you not have been understanding? can they not have been understanding?