English verb conjugation
COULD TWINKLE

Regular verb: twinkle - twinkled - twinkled

Affirmation

Simple form	V-ing form
I could twinkle you could twinkle he could twinkle we could twinkle you could twinkle they could twinkle	I could be twinkling you could be twinkling he could be twinkling we could be twinkling you could be twinkling they could be twinkling
Perfect	V-ing perfect
I could have twinkled you could have twinkled he could have twinkled we could have twinkled you could have twinkled they could have twinkled	I could have been twinkling you could have been twinkling he could have been twinkling we could have been twinkling you could have been twinkling they could have been twinkling

Negation

Simple form	V-ing form
I couldn't twinkle you couldn't twinkle he couldn't twinkle we couldn't twinkle you couldn't twinkle they couldn't twinkle	I couldn't be twinkling you couldn't be twinkling he couldn't be twinkling we couldn't be twinkling you couldn't be twinkling they couldn't be twinkling
Perfect	V-ing perfect
I couldn't have twinkled you couldn't have twinkled he couldn't have twinkled we couldn't have twinkled you couldn't have twinkled they couldn't have twinkled	I couldn't have been twinkling you couldn't have been twinkling he couldn't have been twinkling we couldn't have been twinkling you couldn't have been twinkling they couldn't have been twinkling

Interrogative form

Simple form	V-ing form
could I twinkle? could you twinkle? could he twinkle? could we twinkle? could you twinkle? could they twinkle?	could I be twinkling? could you be twinkling? could he be twinkling? could we be twinkling? could you be twinkling? could they be twinkling?
Perfect	V-ing perfect
could I have twinkled? could you have twinkled? could he have twinkled? could we have twinkled? could you have twinkled? could they have twinkled?	could I have been twinkling? could you have been twinkling? could he have been twinkling? could we have been twinkling? could you have been twinkling? could they have been twinkling?

Interro-negative form

Simple form	V-ing form
couldn't I twinkle? couldn't you twinkle? couldn't he twinkle? couldn't we twinkle? couldn't you twinkle? couldn't they twinkle?	couldn't I be twinkling? couldn't you be twinkling? couldn't he be twinkling? couldn't we be twinkling? couldn't you be twinkling? couldn't they be twinkling?
Perfect	V-ing perfect
couldn't I have twinkled? couldn't you have twinkled? couldn't he have twinkled? couldn't we have twinkled? couldn't you have twinkled? couldn't they have twinkled?	couldn't I have been twinkling? couldn't you have been twinkling? couldn't he have been twinkling? couldn't we have been twinkling? couldn't you have been twinkling? couldn't they have been twinkling?