I could exercise you could exercise she could exercise we could exercise you could exercise they could exercise
V-ing form
I could be exercising you could be exercising she could be exercising we could be exercising you could be exercising they could be exercising
Perfect
I could have exercised you could have exercised she could have exercised we could have exercised you could have exercised they could have exercised
V-ing perfect
I could have been exercising you could have been exercising she could have been exercising we could have been exercising you could have been exercising they could have been exercising
Negation
Simple form
I could not exercise you could not exercise she could not exercise we could not exercise you could not exercise they could not exercise
V-ing form
I could not be exercising you could not be exercising she could not be exercising we could not be exercising you could not be exercising they could not be exercising
Perfect
I could not have exercised you could not have exercised she could not have exercised we could not have exercised you could not have exercised they could not have exercised
V-ing perfect
I could not have been exercising you could not have been exercising she could not have been exercising we could not have been exercising you could not have been exercising they could not have been exercising
Interrogative form
Simple form
could I exercise? could you exercise? could she exercise? could we exercise? could you exercise? could they exercise?
V-ing form
could I be exercising? could you be exercising? could she be exercising? could we be exercising? could you be exercising? could they be exercising?
Perfect
could I have exercised? could you have exercised? could she have exercised? could we have exercised? could you have exercised? could they have exercised?
V-ing perfect
could I have been exercising? could you have been exercising? could she have been exercising? could we have been exercising? could you have been exercising? could they have been exercising?
Interro-negative form
Simple form
could I not exercise? could you not exercise? could she not exercise? could we not exercise? could you not exercise? could they not exercise?
V-ing form
could I not be exercising? could you not be exercising? could she not be exercising? could we not be exercising? could you not be exercising? could they not be exercising?
Perfect
could I not have exercised? could you not have exercised? could she not have exercised? could we not have exercised? could you not have exercised? could they not have exercised?
V-ing perfect
could I not have been exercising? could you not have been exercising? could she not have been exercising? could we not have been exercising? could you not have been exercising? could they not have been exercising?