I could concrete you could concrete he could concrete we could concrete you could concrete they could concrete
V-ing form
I could be concreting you could be concreting he could be concreting we could be concreting you could be concreting they could be concreting
Perfect
I could have concreted you could have concreted he could have concreted we could have concreted you could have concreted they could have concreted
V-ing perfect
I could have been concreting you could have been concreting he could have been concreting we could have been concreting you could have been concreting they could have been concreting
Negation
Simple form
I could not concrete you could not concrete he could not concrete we could not concrete you could not concrete they could not concrete
V-ing form
I could not be concreting you could not be concreting he could not be concreting we could not be concreting you could not be concreting they could not be concreting
Perfect
I could not have concreted you could not have concreted he could not have concreted we could not have concreted you could not have concreted they could not have concreted
V-ing perfect
I could not have been concreting you could not have been concreting he could not have been concreting we could not have been concreting you could not have been concreting they could not have been concreting
Interrogative form
Simple form
could I concrete? could you concrete? could he concrete? could we concrete? could you concrete? could they concrete?
V-ing form
could I be concreting? could you be concreting? could he be concreting? could we be concreting? could you be concreting? could they be concreting?
Perfect
could I have concreted? could you have concreted? could he have concreted? could we have concreted? could you have concreted? could they have concreted?
V-ing perfect
could I have been concreting? could you have been concreting? could he have been concreting? could we have been concreting? could you have been concreting? could they have been concreting?
Interro-negative form
Simple form
could I not concrete? could you not concrete? could he not concrete? could we not concrete? could you not concrete? could they not concrete?
V-ing form
could I not be concreting? could you not be concreting? could he not be concreting? could we not be concreting? could you not be concreting? could they not be concreting?
Perfect
could I not have concreted? could you not have concreted? could he not have concreted? could we not have concreted? could you not have concreted? could they not have concreted?
V-ing perfect
could I not have been concreting? could you not have been concreting? could he not have been concreting? could we not have been concreting? could you not have been concreting? could they not have been concreting?