English verb conjugation
COULD MUTTER

Regular verb: mutter - muttered - muttered

Affirmation

Simple form	V-ing form
I could mutter you could mutter she could mutter we could mutter you could mutter they could mutter	I could be muttering you could be muttering she could be muttering we could be muttering you could be muttering they could be muttering
Perfect	V-ing perfect
I could have muttered you could have muttered she could have muttered we could have muttered you could have muttered they could have muttered	I could have been muttering you could have been muttering she could have been muttering we could have been muttering you could have been muttering they could have been muttering

Negation

Simple form	V-ing form
I couldn't mutter you couldn't mutter she couldn't mutter we couldn't mutter you couldn't mutter they couldn't mutter	I couldn't be muttering you couldn't be muttering she couldn't be muttering we couldn't be muttering you couldn't be muttering they couldn't be muttering
Perfect	V-ing perfect
I couldn't have muttered you couldn't have muttered she couldn't have muttered we couldn't have muttered you couldn't have muttered they couldn't have muttered	I couldn't have been muttering you couldn't have been muttering she couldn't have been muttering we couldn't have been muttering you couldn't have been muttering they couldn't have been muttering

Interrogative form

Simple form	V-ing form
could I mutter? could you mutter? could she mutter? could we mutter? could you mutter? could they mutter?	could I be muttering? could you be muttering? could she be muttering? could we be muttering? could you be muttering? could they be muttering?
Perfect	V-ing perfect
could I have muttered? could you have muttered? could she have muttered? could we have muttered? could you have muttered? could they have muttered?	could I have been muttering? could you have been muttering? could she have been muttering? could we have been muttering? could you have been muttering? could they have been muttering?

Interro-negative form

Simple form	V-ing form
couldn't I mutter? couldn't you mutter? couldn't she mutter? couldn't we mutter? couldn't you mutter? couldn't they mutter?	couldn't I be muttering? couldn't you be muttering? couldn't she be muttering? couldn't we be muttering? couldn't you be muttering? couldn't they be muttering?
Perfect	V-ing perfect
couldn't I have muttered? couldn't you have muttered? couldn't she have muttered? couldn't we have muttered? couldn't you have muttered? couldn't they have muttered?	couldn't I have been muttering? couldn't you have been muttering? couldn't she have been muttering? couldn't we have been muttering? couldn't you have been muttering? couldn't they have been muttering?