I could upload you could upload he could upload we could upload you could upload they could upload
V-ing form
I could be uploading you could be uploading he could be uploading we could be uploading you could be uploading they could be uploading
Perfect
I could have uploaded you could have uploaded he could have uploaded we could have uploaded you could have uploaded they could have uploaded
V-ing perfect
I could have been uploading you could have been uploading he could have been uploading we could have been uploading you could have been uploading they could have been uploading
Negation
Simple form
I couldn't upload you couldn't upload he couldn't upload we couldn't upload you couldn't upload they couldn't upload
V-ing form
I couldn't be uploading you couldn't be uploading he couldn't be uploading we couldn't be uploading you couldn't be uploading they couldn't be uploading
Perfect
I couldn't have uploaded you couldn't have uploaded he couldn't have uploaded we couldn't have uploaded you couldn't have uploaded they couldn't have uploaded
V-ing perfect
I couldn't have been uploading you couldn't have been uploading he couldn't have been uploading we couldn't have been uploading you couldn't have been uploading they couldn't have been uploading
Interrogative form
Simple form
could I upload? could you upload? could he upload? could we upload? could you upload? could they upload?
V-ing form
could I be uploading? could you be uploading? could he be uploading? could we be uploading? could you be uploading? could they be uploading?
Perfect
could I have uploaded? could you have uploaded? could he have uploaded? could we have uploaded? could you have uploaded? could they have uploaded?
V-ing perfect
could I have been uploading? could you have been uploading? could he have been uploading? could we have been uploading? could you have been uploading? could they have been uploading?
Interro-negative form
Simple form
couldn't I upload? couldn't you upload? couldn't he upload? couldn't we upload? couldn't you upload? couldn't they upload?
V-ing form
couldn't I be uploading? couldn't you be uploading? couldn't he be uploading? couldn't we be uploading? couldn't you be uploading? couldn't they be uploading?
Perfect
couldn't I have uploaded? couldn't you have uploaded? couldn't he have uploaded? couldn't we have uploaded? couldn't you have uploaded? couldn't they have uploaded?
V-ing perfect
couldn't I have been uploading? couldn't you have been uploading? couldn't he have been uploading? couldn't we have been uploading? couldn't you have been uploading? couldn't they have been uploading?