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