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