I could gravitate you could gravitate he could gravitate we could gravitate you could gravitate they could gravitate
V-ing form
I could be gravitating you could be gravitating he could be gravitating we could be gravitating you could be gravitating they could be gravitating
Perfect
I could have gravitated you could have gravitated he could have gravitated we could have gravitated you could have gravitated they could have gravitated
V-ing perfect
I could have been gravitating you could have been gravitating he could have been gravitating we could have been gravitating you could have been gravitating they could have been gravitating
Negation
Simple form
I couldn't gravitate you couldn't gravitate he couldn't gravitate we couldn't gravitate you couldn't gravitate they couldn't gravitate
V-ing form
I couldn't be gravitating you couldn't be gravitating he couldn't be gravitating we couldn't be gravitating you couldn't be gravitating they couldn't be gravitating
Perfect
I couldn't have gravitated you couldn't have gravitated he couldn't have gravitated we couldn't have gravitated you couldn't have gravitated they couldn't have gravitated
V-ing perfect
I couldn't have been gravitating you couldn't have been gravitating he couldn't have been gravitating we couldn't have been gravitating you couldn't have been gravitating they couldn't have been gravitating
Interrogative form
Simple form
could I gravitate? could you gravitate? could he gravitate? could we gravitate? could you gravitate? could they gravitate?
V-ing form
could I be gravitating? could you be gravitating? could he be gravitating? could we be gravitating? could you be gravitating? could they be gravitating?
Perfect
could I have gravitated? could you have gravitated? could he have gravitated? could we have gravitated? could you have gravitated? could they have gravitated?
V-ing perfect
could I have been gravitating? could you have been gravitating? could he have been gravitating? could we have been gravitating? could you have been gravitating? could they have been gravitating?
Interro-negative form
Simple form
couldn't I gravitate? couldn't you gravitate? couldn't he gravitate? couldn't we gravitate? couldn't you gravitate? couldn't they gravitate?
V-ing form
couldn't I be gravitating? couldn't you be gravitating? couldn't he be gravitating? couldn't we be gravitating? couldn't you be gravitating? couldn't they be gravitating?
Perfect
couldn't I have gravitated? couldn't you have gravitated? couldn't he have gravitated? couldn't we have gravitated? couldn't you have gravitated? couldn't they have gravitated?
V-ing perfect
couldn't I have been gravitating? couldn't you have been gravitating? couldn't he have been gravitating? couldn't we have been gravitating? couldn't you have been gravitating? couldn't they have been gravitating?