I could photosynthesise you could photosynthesise she could photosynthesise we could photosynthesise you could photosynthesise they could photosynthesise
V-ing form
I could be photosynthesising you could be photosynthesising she could be photosynthesising we could be photosynthesising you could be photosynthesising they could be photosynthesising
Perfect
I could have photosynthesised you could have photosynthesised she could have photosynthesised we could have photosynthesised you could have photosynthesised they could have photosynthesised
V-ing perfect
I could have been photosynthesising you could have been photosynthesising she could have been photosynthesising we could have been photosynthesising you could have been photosynthesising they could have been photosynthesising
Negation
Simple form
I could not photosynthesise you could not photosynthesise she could not photosynthesise we could not photosynthesise you could not photosynthesise they could not photosynthesise
V-ing form
I could not be photosynthesising you could not be photosynthesising she could not be photosynthesising we could not be photosynthesising you could not be photosynthesising they could not be photosynthesising
Perfect
I could not have photosynthesised you could not have photosynthesised she could not have photosynthesised we could not have photosynthesised you could not have photosynthesised they could not have photosynthesised
V-ing perfect
I could not have been photosynthesising you could not have been photosynthesising she could not have been photosynthesising we could not have been photosynthesising you could not have been photosynthesising they could not have been photosynthesising
Interrogative form
Simple form
could I photosynthesise? could you photosynthesise? could she photosynthesise? could we photosynthesise? could you photosynthesise? could they photosynthesise?
V-ing form
could I be photosynthesising? could you be photosynthesising? could she be photosynthesising? could we be photosynthesising? could you be photosynthesising? could they be photosynthesising?
Perfect
could I have photosynthesised? could you have photosynthesised? could she have photosynthesised? could we have photosynthesised? could you have photosynthesised? could they have photosynthesised?
V-ing perfect
could I have been photosynthesising? could you have been photosynthesising? could she have been photosynthesising? could we have been photosynthesising? could you have been photosynthesising? could they have been photosynthesising?
Interro-negative form
Simple form
could I not photosynthesise? could you not photosynthesise? could she not photosynthesise? could we not photosynthesise? could you not photosynthesise? could they not photosynthesise?
V-ing form
could I not be photosynthesising? could you not be photosynthesising? could she not be photosynthesising? could we not be photosynthesising? could you not be photosynthesising? could they not be photosynthesising?
Perfect
could I not have photosynthesised? could you not have photosynthesised? could she not have photosynthesised? could we not have photosynthesised? could you not have photosynthesised? could they not have photosynthesised?
V-ing perfect
could I not have been photosynthesising? could you not have been photosynthesising? could she not have been photosynthesising? could we not have been photosynthesising? could you not have been photosynthesising? could they not have been photosynthesising?