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