English verb conjugation
CAN SUSTAIN

Regular verb: sustain - sustained - sustained

Affirmation

Simple form	V-ing form
I can sustain you can sustain he can sustain we can sustain you can sustain they can sustain	I can be sustaining you can be sustaining he can be sustaining we can be sustaining you can be sustaining they can be sustaining
Perfect	V-ing perfect
I can have sustained you can have sustained he can have sustained we can have sustained you can have sustained they can have sustained	I can have been sustaining you can have been sustaining he can have been sustaining we can have been sustaining you can have been sustaining they can have been sustaining

Negation

Simple form	V-ing form
I cannot sustain you cannot sustain he cannot sustain we cannot sustain you cannot sustain they cannot sustain	I cannot be sustaining you cannot be sustaining he cannot be sustaining we cannot be sustaining you cannot be sustaining they cannot be sustaining
Perfect	V-ing perfect
I cannot have sustained you cannot have sustained he cannot have sustained we cannot have sustained you cannot have sustained they cannot have sustained	I cannot have been sustaining you cannot have been sustaining he cannot have been sustaining we cannot have been sustaining you cannot have been sustaining they cannot have been sustaining

Interrogative form

Simple form	V-ing form
can I sustain? can you sustain? can he sustain? can we sustain? can you sustain? can they sustain?	can I be sustaining? can you be sustaining? can he be sustaining? can we be sustaining? can you be sustaining? can they be sustaining?
Perfect	V-ing perfect
can I have sustained? can you have sustained? can he have sustained? can we have sustained? can you have sustained? can they have sustained?	can I have been sustaining? can you have been sustaining? can he have been sustaining? can we have been sustaining? can you have been sustaining? can they have been sustaining?

Interro-negative form

Simple form	V-ing form
can I not sustain? can you not sustain? can he not sustain? can we not sustain? can you not sustain? can they not sustain?	can I not be sustaining? can you not be sustaining? can he not be sustaining? can we not be sustaining? can you not be sustaining? can they not be sustaining?
Perfect	V-ing perfect
can I not have sustained? can you not have sustained? can he not have sustained? can we not have sustained? can you not have sustained? can they not have sustained?	can I not have been sustaining? can you not have been sustaining? can he not have been sustaining? can we not have been sustaining? can you not have been sustaining? can they not have been sustaining?