I could bobsled you could bobsled he could bobsled we could bobsled you could bobsled they could bobsled
V-ing form
I could be bobsleding you could be bobsleding he could be bobsleding we could be bobsleding you could be bobsleding they could be bobsleding
Perfect
I could have bobsleded you could have bobsleded he could have bobsleded we could have bobsleded you could have bobsleded they could have bobsleded
V-ing perfect
I could have been bobsleding you could have been bobsleding he could have been bobsleding we could have been bobsleding you could have been bobsleding they could have been bobsleding
Negation
Simple form
I could not bobsled you could not bobsled he could not bobsled we could not bobsled you could not bobsled they could not bobsled
V-ing form
I could not be bobsleding you could not be bobsleding he could not be bobsleding we could not be bobsleding you could not be bobsleding they could not be bobsleding
Perfect
I could not have bobsleded you could not have bobsleded he could not have bobsleded we could not have bobsleded you could not have bobsleded they could not have bobsleded
V-ing perfect
I could not have been bobsleding you could not have been bobsleding he could not have been bobsleding we could not have been bobsleding you could not have been bobsleding they could not have been bobsleding
Interrogative form
Simple form
could I bobsled? could you bobsled? could he bobsled? could we bobsled? could you bobsled? could they bobsled?
V-ing form
could I be bobsleding? could you be bobsleding? could he be bobsleding? could we be bobsleding? could you be bobsleding? could they be bobsleding?
Perfect
could I have bobsleded? could you have bobsleded? could he have bobsleded? could we have bobsleded? could you have bobsleded? could they have bobsleded?
V-ing perfect
could I have been bobsleding? could you have been bobsleding? could he have been bobsleding? could we have been bobsleding? could you have been bobsleding? could they have been bobsleding?
Interro-negative form
Simple form
could I not bobsled? could you not bobsled? could he not bobsled? could we not bobsled? could you not bobsled? could they not bobsled?
V-ing form
could I not be bobsleding? could you not be bobsleding? could he not be bobsleding? could we not be bobsleding? could you not be bobsleding? could they not be bobsleding?
Perfect
could I not have bobsleded? could you not have bobsleded? could he not have bobsleded? could we not have bobsleded? could you not have bobsleded? could they not have bobsleded?
V-ing perfect
could I not have been bobsleding? could you not have been bobsleding? could he not have been bobsleding? could we not have been bobsleding? could you not have been bobsleding? could they not have been bobsleding?