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 couldn't recycle you couldn't recycle he couldn't recycle we couldn't recycle you couldn't recycle they couldn't recycle
V-ing form
I couldn't be recycling you couldn't be recycling he couldn't be recycling we couldn't be recycling you couldn't be recycling they couldn't be recycling
Perfect
I couldn't have recycled you couldn't have recycled he couldn't have recycled we couldn't have recycled you couldn't have recycled they couldn't have recycled
V-ing perfect
I couldn't have been recycling you couldn't have been recycling he couldn't have been recycling we couldn't have been recycling you couldn't have been recycling they couldn't 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
couldn't I recycle? couldn't you recycle? couldn't he recycle? couldn't we recycle? couldn't you recycle? couldn't they recycle?
V-ing form
couldn't I be recycling? couldn't you be recycling? couldn't he be recycling? couldn't we be recycling? couldn't you be recycling? couldn't they be recycling?
Perfect
couldn't I have recycled? couldn't you have recycled? couldn't he have recycled? couldn't we have recycled? couldn't you have recycled? couldn't they have recycled?
V-ing perfect
couldn't I have been recycling? couldn't you have been recycling? couldn't he have been recycling? couldn't we have been recycling? couldn't you have been recycling? couldn't they have been recycling?