I could lecture you could lecture he could lecture we could lecture you could lecture they could lecture
V-ing form
I could be lecturing you could be lecturing he could be lecturing we could be lecturing you could be lecturing they could be lecturing
Perfect
I could have lectured you could have lectured he could have lectured we could have lectured you could have lectured they could have lectured
V-ing perfect
I could have been lecturing you could have been lecturing he could have been lecturing we could have been lecturing you could have been lecturing they could have been lecturing
Negation
Simple form
I could not lecture you could not lecture he could not lecture we could not lecture you could not lecture they could not lecture
V-ing form
I could not be lecturing you could not be lecturing he could not be lecturing we could not be lecturing you could not be lecturing they could not be lecturing
Perfect
I could not have lectured you could not have lectured he could not have lectured we could not have lectured you could not have lectured they could not have lectured
V-ing perfect
I could not have been lecturing you could not have been lecturing he could not have been lecturing we could not have been lecturing you could not have been lecturing they could not have been lecturing
Interrogative form
Simple form
could I lecture? could you lecture? could he lecture? could we lecture? could you lecture? could they lecture?
V-ing form
could I be lecturing? could you be lecturing? could he be lecturing? could we be lecturing? could you be lecturing? could they be lecturing?
Perfect
could I have lectured? could you have lectured? could he have lectured? could we have lectured? could you have lectured? could they have lectured?
V-ing perfect
could I have been lecturing? could you have been lecturing? could he have been lecturing? could we have been lecturing? could you have been lecturing? could they have been lecturing?
Interro-negative form
Simple form
could I not lecture? could you not lecture? could he not lecture? could we not lecture? could you not lecture? could they not lecture?
V-ing form
could I not be lecturing? could you not be lecturing? could he not be lecturing? could we not be lecturing? could you not be lecturing? could they not be lecturing?
Perfect
could I not have lectured? could you not have lectured? could he not have lectured? could we not have lectured? could you not have lectured? could they not have lectured?
V-ing perfect
could I not have been lecturing? could you not have been lecturing? could he not have been lecturing? could we not have been lecturing? could you not have been lecturing? could they not have been lecturing?