I could deduce you could deduce she could deduce we could deduce you could deduce they could deduce
V-ing form
I could be deducing you could be deducing she could be deducing we could be deducing you could be deducing they could be deducing
Perfect
I could have deduced you could have deduced she could have deduced we could have deduced you could have deduced they could have deduced
V-ing perfect
I could have been deducing you could have been deducing she could have been deducing we could have been deducing you could have been deducing they could have been deducing
Negation
Simple form
I couldn't deduce you couldn't deduce she couldn't deduce we couldn't deduce you couldn't deduce they couldn't deduce
V-ing form
I couldn't be deducing you couldn't be deducing she couldn't be deducing we couldn't be deducing you couldn't be deducing they couldn't be deducing
Perfect
I couldn't have deduced you couldn't have deduced she couldn't have deduced we couldn't have deduced you couldn't have deduced they couldn't have deduced
V-ing perfect
I couldn't have been deducing you couldn't have been deducing she couldn't have been deducing we couldn't have been deducing you couldn't have been deducing they couldn't have been deducing
Interrogative form
Simple form
could I deduce? could you deduce? could she deduce? could we deduce? could you deduce? could they deduce?
V-ing form
could I be deducing? could you be deducing? could she be deducing? could we be deducing? could you be deducing? could they be deducing?
Perfect
could I have deduced? could you have deduced? could she have deduced? could we have deduced? could you have deduced? could they have deduced?
V-ing perfect
could I have been deducing? could you have been deducing? could she have been deducing? could we have been deducing? could you have been deducing? could they have been deducing?
Interro-negative form
Simple form
couldn't I deduce? couldn't you deduce? couldn't she deduce? couldn't we deduce? couldn't you deduce? couldn't they deduce?
V-ing form
couldn't I be deducing? couldn't you be deducing? couldn't she be deducing? couldn't we be deducing? couldn't you be deducing? couldn't they be deducing?
Perfect
couldn't I have deduced? couldn't you have deduced? couldn't she have deduced? couldn't we have deduced? couldn't you have deduced? couldn't they have deduced?
V-ing perfect
couldn't I have been deducing? couldn't you have been deducing? couldn't she have been deducing? couldn't we have been deducing? couldn't you have been deducing? couldn't they have been deducing?