I must crinkle you must crinkle she must crinkle we must crinkle you must crinkle they must crinkle
V-ing form
I must be crinkling you must be crinkling she must be crinkling we must be crinkling you must be crinkling they must be crinkling
Perfect
I must have crinkled you must have crinkled she must have crinkled we must have crinkled you must have crinkled they must have crinkled
V-ing perfect
I must have been crinkling you must have been crinkling she must have been crinkling we must have been crinkling you must have been crinkling they must have been crinkling
Negation
Simple form
I must not crinkle you must not crinkle she must not crinkle we must not crinkle you must not crinkle they must not crinkle
V-ing form
I must not be crinkling you must not be crinkling she must not be crinkling we must not be crinkling you must not be crinkling they must not be crinkling
Perfect
I must not have crinkled you must not have crinkled she must not have crinkled we must not have crinkled you must not have crinkled they must not have crinkled
V-ing perfect
I must not have been crinkling you must not have been crinkling she must not have been crinkling we must not have been crinkling you must not have been crinkling they must not have been crinkling
Interrogative form
Simple form
must I crinkle? must you crinkle? must she crinkle? must we crinkle? must you crinkle? must they crinkle?
V-ing form
must I be crinkling? must you be crinkling? must she be crinkling? must we be crinkling? must you be crinkling? must they be crinkling?
Perfect
must I have crinkled? must you have crinkled? must she have crinkled? must we have crinkled? must you have crinkled? must they have crinkled?
V-ing perfect
must I have been crinkling? must you have been crinkling? must she have been crinkling? must we have been crinkling? must you have been crinkling? must they have been crinkling?
Interro-negative form
Simple form
must I not crinkle? must you not crinkle? must she not crinkle? must we not crinkle? must you not crinkle? must they not crinkle?
V-ing form
must I not be crinkling? must you not be crinkling? must she not be crinkling? must we not be crinkling? must you not be crinkling? must they not be crinkling?
Perfect
must I not have crinkled? must you not have crinkled? must she not have crinkled? must we not have crinkled? must you not have crinkled? must they not have crinkled?
V-ing perfect
must I not have been crinkling? must you not have been crinkling? must she not have been crinkling? must we not have been crinkling? must you not have been crinkling? must they not have been crinkling?