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