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