I could recycle you could recycle he could recycle we could recycle you could recycle they could recycle
V-ing form
I could be recycling you could be recycling he could be recycling we could be recycling you could be recycling they could be recycling
Perfect
I could have recycled you could have recycled he could have recycled we could have recycled you could have recycled they could have recycled
V-ing perfect
I could have been recycling you could have been recycling he could have been recycling we could have been recycling you could have been recycling they could have been recycling
Negation
Simple form
I could not recycle you could not recycle he could not recycle we could not recycle you could not recycle they could not recycle
V-ing form
I could not be recycling you could not be recycling he could not be recycling we could not be recycling you could not be recycling they could not be recycling
Perfect
I could not have recycled you could not have recycled he could not have recycled we could not have recycled you could not have recycled they could not have recycled
V-ing perfect
I could not have been recycling you could not have been recycling he could not have been recycling we could not have been recycling you could not have been recycling they could not have been recycling
Interrogative form
Simple form
could I recycle? could you recycle? could he recycle? could we recycle? could you recycle? could they recycle?
V-ing form
could I be recycling? could you be recycling? could he be recycling? could we be recycling? could you be recycling? could they be recycling?
Perfect
could I have recycled? could you have recycled? could he have recycled? could we have recycled? could you have recycled? could they have recycled?
V-ing perfect
could I have been recycling? could you have been recycling? could he have been recycling? could we have been recycling? could you have been recycling? could they have been recycling?
Interro-negative form
Simple form
could I not recycle? could you not recycle? could he not recycle? could we not recycle? could you not recycle? could they not recycle?
V-ing form
could I not be recycling? could you not be recycling? could he not be recycling? could we not be recycling? could you not be recycling? could they not be recycling?
Perfect
could I not have recycled? could you not have recycled? could he not have recycled? could we not have recycled? could you not have recycled? could they not have recycled?
V-ing perfect
could I not have been recycling? could you not have been recycling? could he not have been recycling? could we not have been recycling? could you not have been recycling? could they not have been recycling?