I could low you could low he could low we could low you could low they could low
V-ing form
I could be lowing you could be lowing he could be lowing we could be lowing you could be lowing they could be lowing
Perfect
I could have lowed you could have lowed he could have lowed we could have lowed you could have lowed they could have lowed
V-ing perfect
I could have been lowing you could have been lowing he could have been lowing we could have been lowing you could have been lowing they could have been lowing
Negation
Simple form
I could not low you could not low he could not low we could not low you could not low they could not low
V-ing form
I could not be lowing you could not be lowing he could not be lowing we could not be lowing you could not be lowing they could not be lowing
Perfect
I could not have lowed you could not have lowed he could not have lowed we could not have lowed you could not have lowed they could not have lowed
V-ing perfect
I could not have been lowing you could not have been lowing he could not have been lowing we could not have been lowing you could not have been lowing they could not have been lowing
Interrogative form
Simple form
could I low? could you low? could he low? could we low? could you low? could they low?
V-ing form
could I be lowing? could you be lowing? could he be lowing? could we be lowing? could you be lowing? could they be lowing?
Perfect
could I have lowed? could you have lowed? could he have lowed? could we have lowed? could you have lowed? could they have lowed?
V-ing perfect
could I have been lowing? could you have been lowing? could he have been lowing? could we have been lowing? could you have been lowing? could they have been lowing?
Interro-negative form
Simple form
could I not low? could you not low? could he not low? could we not low? could you not low? could they not low?
V-ing form
could I not be lowing? could you not be lowing? could he not be lowing? could we not be lowing? could you not be lowing? could they not be lowing?
Perfect
could I not have lowed? could you not have lowed? could he not have lowed? could we not have lowed? could you not have lowed? could they not have lowed?
V-ing perfect
could I not have been lowing? could you not have been lowing? could he not have been lowing? could we not have been lowing? could you not have been lowing? could they not have been lowing?