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