English verb conjugation
COULD COMBUST

Regular verb: combust - combusted - combusted

Affirmation

Simple form	V-ing form
I could combust you could combust he could combust we could combust you could combust they could combust	I could be combusting you could be combusting he could be combusting we could be combusting you could be combusting they could be combusting
Perfect	V-ing perfect
I could have combusted you could have combusted he could have combusted we could have combusted you could have combusted they could have combusted	I could have been combusting you could have been combusting he could have been combusting we could have been combusting you could have been combusting they could have been combusting

Negation

Simple form	V-ing form
I could not combust you could not combust he could not combust we could not combust you could not combust they could not combust	I could not be combusting you could not be combusting he could not be combusting we could not be combusting you could not be combusting they could not be combusting
Perfect	V-ing perfect
I could not have combusted you could not have combusted he could not have combusted we could not have combusted you could not have combusted they could not have combusted	I could not have been combusting you could not have been combusting he could not have been combusting we could not have been combusting you could not have been combusting they could not have been combusting

Interrogative form

Simple form	V-ing form
could I combust? could you combust? could he combust? could we combust? could you combust? could they combust?	could I be combusting? could you be combusting? could he be combusting? could we be combusting? could you be combusting? could they be combusting?
Perfect	V-ing perfect
could I have combusted? could you have combusted? could he have combusted? could we have combusted? could you have combusted? could they have combusted?	could I have been combusting? could you have been combusting? could he have been combusting? could we have been combusting? could you have been combusting? could they have been combusting?

Interro-negative form

Simple form	V-ing form
could I not combust? could you not combust? could he not combust? could we not combust? could you not combust? could they not combust?	could I not be combusting? could you not be combusting? could he not be combusting? could we not be combusting? could you not be combusting? could they not be combusting?
Perfect	V-ing perfect
could I not have combusted? could you not have combusted? could he not have combusted? could we not have combusted? could you not have combusted? could they not have combusted?	could I not have been combusting? could you not have been combusting? could he not have been combusting? could we not have been combusting? could you not have been combusting? could they not have been combusting?