English verb conjugation
COULD PERCUSS

Regular verb: percuss - percussed - percussed

Affirmation

Simple form	V-ing form
I could percuss you could percuss he could percuss we could percuss you could percuss they could percuss	I could be percussing you could be percussing he could be percussing we could be percussing you could be percussing they could be percussing
Perfect	V-ing perfect
I could have percussed you could have percussed he could have percussed we could have percussed you could have percussed they could have percussed	I could have been percussing you could have been percussing he could have been percussing we could have been percussing you could have been percussing they could have been percussing

Negation

Simple form	V-ing form
I couldn't percuss you couldn't percuss he couldn't percuss we couldn't percuss you couldn't percuss they couldn't percuss	I couldn't be percussing you couldn't be percussing he couldn't be percussing we couldn't be percussing you couldn't be percussing they couldn't be percussing
Perfect	V-ing perfect
I couldn't have percussed you couldn't have percussed he couldn't have percussed we couldn't have percussed you couldn't have percussed they couldn't have percussed	I couldn't have been percussing you couldn't have been percussing he couldn't have been percussing we couldn't have been percussing you couldn't have been percussing they couldn't have been percussing

Interrogative form

Simple form	V-ing form
could I percuss? could you percuss? could he percuss? could we percuss? could you percuss? could they percuss?	could I be percussing? could you be percussing? could he be percussing? could we be percussing? could you be percussing? could they be percussing?
Perfect	V-ing perfect
could I have percussed? could you have percussed? could he have percussed? could we have percussed? could you have percussed? could they have percussed?	could I have been percussing? could you have been percussing? could he have been percussing? could we have been percussing? could you have been percussing? could they have been percussing?

Interro-negative form

Simple form	V-ing form
couldn't I percuss? couldn't you percuss? couldn't he percuss? couldn't we percuss? couldn't you percuss? couldn't they percuss?	couldn't I be percussing? couldn't you be percussing? couldn't he be percussing? couldn't we be percussing? couldn't you be percussing? couldn't they be percussing?
Perfect	V-ing perfect
couldn't I have percussed? couldn't you have percussed? couldn't he have percussed? couldn't we have percussed? couldn't you have percussed? couldn't they have percussed?	couldn't I have been percussing? couldn't you have been percussing? couldn't he have been percussing? couldn't we have been percussing? couldn't you have been percussing? couldn't they have been percussing?