I could preguarantee you could preguarantee she could preguarantee we could preguarantee you could preguarantee they could preguarantee
V-ing form
I could be preguaranteeing you could be preguaranteeing she could be preguaranteeing we could be preguaranteeing you could be preguaranteeing they could be preguaranteeing
Perfect
I could have preguaranteed you could have preguaranteed she could have preguaranteed we could have preguaranteed you could have preguaranteed they could have preguaranteed
V-ing perfect
I could have been preguaranteeing you could have been preguaranteeing she could have been preguaranteeing we could have been preguaranteeing you could have been preguaranteeing they could have been preguaranteeing
Negation
Simple form
I couldn't preguarantee you couldn't preguarantee she couldn't preguarantee we couldn't preguarantee you couldn't preguarantee they couldn't preguarantee
V-ing form
I couldn't be preguaranteeing you couldn't be preguaranteeing she couldn't be preguaranteeing we couldn't be preguaranteeing you couldn't be preguaranteeing they couldn't be preguaranteeing
Perfect
I couldn't have preguaranteed you couldn't have preguaranteed she couldn't have preguaranteed we couldn't have preguaranteed you couldn't have preguaranteed they couldn't have preguaranteed
V-ing perfect
I couldn't have been preguaranteeing you couldn't have been preguaranteeing she couldn't have been preguaranteeing we couldn't have been preguaranteeing you couldn't have been preguaranteeing they couldn't have been preguaranteeing
Interrogative form
Simple form
could I preguarantee? could you preguarantee? could she preguarantee? could we preguarantee? could you preguarantee? could they preguarantee?
V-ing form
could I be preguaranteeing? could you be preguaranteeing? could she be preguaranteeing? could we be preguaranteeing? could you be preguaranteeing? could they be preguaranteeing?
Perfect
could I have preguaranteed? could you have preguaranteed? could she have preguaranteed? could we have preguaranteed? could you have preguaranteed? could they have preguaranteed?
V-ing perfect
could I have been preguaranteeing? could you have been preguaranteeing? could she have been preguaranteeing? could we have been preguaranteeing? could you have been preguaranteeing? could they have been preguaranteeing?
Interro-negative form
Simple form
couldn't I preguarantee? couldn't you preguarantee? couldn't she preguarantee? couldn't we preguarantee? couldn't you preguarantee? couldn't they preguarantee?
V-ing form
couldn't I be preguaranteeing? couldn't you be preguaranteeing? couldn't she be preguaranteeing? couldn't we be preguaranteeing? couldn't you be preguaranteeing? couldn't they be preguaranteeing?
Perfect
couldn't I have preguaranteed? couldn't you have preguaranteed? couldn't she have preguaranteed? couldn't we have preguaranteed? couldn't you have preguaranteed? couldn't they have preguaranteed?
V-ing perfect
couldn't I have been preguaranteeing? couldn't you have been preguaranteeing? couldn't she have been preguaranteeing? couldn't we have been preguaranteeing? couldn't you have been preguaranteeing? couldn't they have been preguaranteeing?