I could shake you could shake he could shake we could shake you could shake they could shake
V-ing form
I could be shaking you could be shaking he could be shaking we could be shaking you could be shaking they could be shaking
Perfect
I could have shaken you could have shaken he could have shaken we could have shaken you could have shaken they could have shaken
V-ing perfect
I could have been shaking you could have been shaking he could have been shaking we could have been shaking you could have been shaking they could have been shaking
Negation
Simple form
I could not shake you could not shake he could not shake we could not shake you could not shake they could not shake
V-ing form
I could not be shaking you could not be shaking he could not be shaking we could not be shaking you could not be shaking they could not be shaking
Perfect
I could not have shaken you could not have shaken he could not have shaken we could not have shaken you could not have shaken they could not have shaken
V-ing perfect
I could not have been shaking you could not have been shaking he could not have been shaking we could not have been shaking you could not have been shaking they could not have been shaking
Interrogative form
Simple form
could I shake? could you shake? could he shake? could we shake? could you shake? could they shake?
V-ing form
could I be shaking? could you be shaking? could he be shaking? could we be shaking? could you be shaking? could they be shaking?
Perfect
could I have shaken? could you have shaken? could he have shaken? could we have shaken? could you have shaken? could they have shaken?
V-ing perfect
could I have been shaking? could you have been shaking? could he have been shaking? could we have been shaking? could you have been shaking? could they have been shaking?
Interro-negative form
Simple form
could I not shake? could you not shake? could he not shake? could we not shake? could you not shake? could they not shake?
V-ing form
could I not be shaking? could you not be shaking? could he not be shaking? could we not be shaking? could you not be shaking? could they not be shaking?
Perfect
could I not have shaken? could you not have shaken? could he not have shaken? could we not have shaken? could you not have shaken? could they not have shaken?
V-ing perfect
could I not have been shaking? could you not have been shaking? could he not have been shaking? could we not have been shaking? could you not have been shaking? could they not have been shaking?