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