English verb conjugation
MUST CRACKLE

Regular verb: crackle - crackled - crackled

Affirmation

Simple form	V-ing form
I must crackle you must crackle she must crackle we must crackle you must crackle they must crackle	I must be crackling you must be crackling she must be crackling we must be crackling you must be crackling they must be crackling
Perfect	V-ing perfect
I must have crackled you must have crackled she must have crackled we must have crackled you must have crackled they must have crackled	I must have been crackling you must have been crackling she must have been crackling we must have been crackling you must have been crackling they must have been crackling

Negation

Simple form	V-ing form
I mustn't crackle you mustn't crackle she mustn't crackle we mustn't crackle you mustn't crackle they mustn't crackle	I mustn't be crackling you mustn't be crackling she mustn't be crackling we mustn't be crackling you mustn't be crackling they mustn't be crackling
Perfect	V-ing perfect
I mustn't have crackled you mustn't have crackled she mustn't have crackled we mustn't have crackled you mustn't have crackled they mustn't have crackled	I mustn't have been crackling you mustn't have been crackling she mustn't have been crackling we mustn't have been crackling you mustn't have been crackling they mustn't have been crackling

Interrogative form

Simple form	V-ing form
must I crackle? must you crackle? must she crackle? must we crackle? must you crackle? must they crackle?	must I be crackling? must you be crackling? must she be crackling? must we be crackling? must you be crackling? must they be crackling?
Perfect	V-ing perfect
must I have crackled? must you have crackled? must she have crackled? must we have crackled? must you have crackled? must they have crackled?	must I have been crackling? must you have been crackling? must she have been crackling? must we have been crackling? must you have been crackling? must they have been crackling?

Interro-negative form

Simple form	V-ing form
mustn't I crackle? mustn't you crackle? mustn't she crackle? mustn't we crackle? mustn't you crackle? mustn't they crackle?	mustn't I be crackling? mustn't you be crackling? mustn't she be crackling? mustn't we be crackling? mustn't you be crackling? mustn't they be crackling?
Perfect	V-ing perfect
mustn't I have crackled? mustn't you have crackled? mustn't she have crackled? mustn't we have crackled? mustn't you have crackled? mustn't they have crackled?	mustn't I have been crackling? mustn't you have been crackling? mustn't she have been crackling? mustn't we have been crackling? mustn't you have been crackling? mustn't they have been crackling?