I could tile you could tile he could tile we could tile you could tile they could tile
V-ing form
I could be tiling you could be tiling he could be tiling we could be tiling you could be tiling they could be tiling
Perfect
I could have tiled you could have tiled he could have tiled we could have tiled you could have tiled they could have tiled
V-ing perfect
I could have been tiling you could have been tiling he could have been tiling we could have been tiling you could have been tiling they could have been tiling
Negation
Simple form
I could not tile you could not tile he could not tile we could not tile you could not tile they could not tile
V-ing form
I could not be tiling you could not be tiling he could not be tiling we could not be tiling you could not be tiling they could not be tiling
Perfect
I could not have tiled you could not have tiled he could not have tiled we could not have tiled you could not have tiled they could not have tiled
V-ing perfect
I could not have been tiling you could not have been tiling he could not have been tiling we could not have been tiling you could not have been tiling they could not have been tiling
Interrogative form
Simple form
could I tile? could you tile? could he tile? could we tile? could you tile? could they tile?
V-ing form
could I be tiling? could you be tiling? could he be tiling? could we be tiling? could you be tiling? could they be tiling?
Perfect
could I have tiled? could you have tiled? could he have tiled? could we have tiled? could you have tiled? could they have tiled?
V-ing perfect
could I have been tiling? could you have been tiling? could he have been tiling? could we have been tiling? could you have been tiling? could they have been tiling?
Interro-negative form
Simple form
could I not tile? could you not tile? could he not tile? could we not tile? could you not tile? could they not tile?
V-ing form
could I not be tiling? could you not be tiling? could he not be tiling? could we not be tiling? could you not be tiling? could they not be tiling?
Perfect
could I not have tiled? could you not have tiled? could he not have tiled? could we not have tiled? could you not have tiled? could they not have tiled?
V-ing perfect
could I not have been tiling? could you not have been tiling? could he not have been tiling? could we not have been tiling? could you not have been tiling? could they not have been tiling?