I ought to preascertain you ought to preascertain she ought to preascertain we ought to preascertain you ought to preascertain they ought to preascertain
V-ing form
I ought to be preascertaining you ought to be preascertaining she ought to be preascertaining we ought to be preascertaining you ought to be preascertaining they ought to be preascertaining
Perfect
I ought to have preascertained you ought to have preascertained she ought to have preascertained we ought to have preascertained you ought to have preascertained they ought to have preascertained
V-ing perfect
I ought to have been preascertaining you ought to have been preascertaining she ought to have been preascertaining we ought to have been preascertaining you ought to have been preascertaining they ought to have been preascertaining
Negation
Simple form
I ought not to preascertain you ought not to preascertain she ought not to preascertain we ought not to preascertain you ought not to preascertain they ought not to preascertain
V-ing form
I ought not to preascertaining you ought not to preascertaining she ought not to preascertaining we ought not to preascertaining you ought not to preascertaining they ought not to preascertaining
Perfect
I ought not to have preascertained you ought not to have preascertained she ought not to have preascertained we ought not to have preascertained you ought not to have preascertained they ought not to have preascertained
V-ing perfect
I ought not to have been preascertaining you ought not to have been preascertaining she ought not to have been preascertaining we ought not to have been preascertaining you ought not to have been preascertaining they ought not to have been preascertaining
Interrogative form
Simple form
ought to I preascertain? ought to you preascertain? ought to she preascertain? ought to we preascertain? ought to you preascertain? ought to they preascertain?
V-ing form
ought to I be preascertaining? ought to you be preascertaining? ought to she be preascertaining? ought to we be preascertaining? ought to you be preascertaining? ought to they be preascertaining?
Perfect
ought to I have preascertained? ought to you have preascertained? ought to she have preascertained? ought to we have preascertained? ought to you have preascertained? ought to they have preascertained?
V-ing perfect
ought to I have been preascertaining? ought to you have been preascertaining? ought to she have been preascertaining? ought to we have been preascertaining? ought to you have been preascertaining? ought to they have been preascertaining?
Interro-negative form
Simple form
ought I not to preascertain? ought you not to preascertain? ought she not to preascertain? ought we not to preascertain? ought you not to preascertain? ought they not to preascertain?
V-ing form
ought I not to be preascertaining? ought you not to be preascertaining? ought she not to be preascertaining? ought we not to be preascertaining? ought you not to be preascertaining? ought they not to be preascertaining?
Perfect
ought I not to have preascertained? ought you not to have preascertained? ought she not to have preascertained? ought we not to have preascertained? ought you not to have preascertained? ought they not to have preascertained?
V-ing perfect
ought I not to have been preascertaining? ought you not to have been preascertaining? ought she not to have been preascertaining? ought we not to have been preascertaining? ought you not to have been preascertaining? ought they not to have been preascertaining?