English verb conjugation
MUST BUCKLE

Regular verb: buckle - buckled - buckled

Affirmation

Simple form	V-ing form
I must buckle you must buckle she must buckle we must buckle you must buckle they must buckle	I must be buckling you must be buckling she must be buckling we must be buckling you must be buckling they must be buckling
Perfect	V-ing perfect
I must have buckled you must have buckled she must have buckled we must have buckled you must have buckled they must have buckled	I must have been buckling you must have been buckling she must have been buckling we must have been buckling you must have been buckling they must have been buckling

Negation

Simple form	V-ing form
I must not buckle you must not buckle she must not buckle we must not buckle you must not buckle they must not buckle	I must not be buckling you must not be buckling she must not be buckling we must not be buckling you must not be buckling they must not be buckling
Perfect	V-ing perfect
I must not have buckled you must not have buckled she must not have buckled we must not have buckled you must not have buckled they must not have buckled	I must not have been buckling you must not have been buckling she must not have been buckling we must not have been buckling you must not have been buckling they must not have been buckling

Interrogative form

Simple form	V-ing form
must I buckle? must you buckle? must she buckle? must we buckle? must you buckle? must they buckle?	must I be buckling? must you be buckling? must she be buckling? must we be buckling? must you be buckling? must they be buckling?
Perfect	V-ing perfect
must I have buckled? must you have buckled? must she have buckled? must we have buckled? must you have buckled? must they have buckled?	must I have been buckling? must you have been buckling? must she have been buckling? must we have been buckling? must you have been buckling? must they have been buckling?

Interro-negative form

Simple form	V-ing form
must I not buckle? must you not buckle? must she not buckle? must we not buckle? must you not buckle? must they not buckle?	must I not be buckling? must you not be buckling? must she not be buckling? must we not be buckling? must you not be buckling? must they not be buckling?
Perfect	V-ing perfect
must I not have buckled? must you not have buckled? must she not have buckled? must we not have buckled? must you not have buckled? must they not have buckled?	must I not have been buckling? must you not have been buckling? must she not have been buckling? must we not have been buckling? must you not have been buckling? must they not have been buckling?