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