I must speculate you must speculate he must speculate we must speculate you must speculate they must speculate
V-ing form
I must be speculating you must be speculating he must be speculating we must be speculating you must be speculating they must be speculating
Perfect
I must have speculated you must have speculated he must have speculated we must have speculated you must have speculated they must have speculated
V-ing perfect
I must have been speculating you must have been speculating he must have been speculating we must have been speculating you must have been speculating they must have been speculating
Negation
Simple form
I mustn't speculate you mustn't speculate he mustn't speculate we mustn't speculate you mustn't speculate they mustn't speculate
V-ing form
I mustn't be speculating you mustn't be speculating he mustn't be speculating we mustn't be speculating you mustn't be speculating they mustn't be speculating
Perfect
I mustn't have speculated you mustn't have speculated he mustn't have speculated we mustn't have speculated you mustn't have speculated they mustn't have speculated
V-ing perfect
I mustn't have been speculating you mustn't have been speculating he mustn't have been speculating we mustn't have been speculating you mustn't have been speculating they mustn't have been speculating
Interrogative form
Simple form
must I speculate? must you speculate? must he speculate? must we speculate? must you speculate? must they speculate?
V-ing form
must I be speculating? must you be speculating? must he be speculating? must we be speculating? must you be speculating? must they be speculating?
Perfect
must I have speculated? must you have speculated? must he have speculated? must we have speculated? must you have speculated? must they have speculated?
V-ing perfect
must I have been speculating? must you have been speculating? must he have been speculating? must we have been speculating? must you have been speculating? must they have been speculating?
Interro-negative form
Simple form
mustn't I speculate? mustn't you speculate? mustn't he speculate? mustn't we speculate? mustn't you speculate? mustn't they speculate?
V-ing form
mustn't I be speculating? mustn't you be speculating? mustn't he be speculating? mustn't we be speculating? mustn't you be speculating? mustn't they be speculating?
Perfect
mustn't I have speculated? mustn't you have speculated? mustn't he have speculated? mustn't we have speculated? mustn't you have speculated? mustn't they have speculated?
V-ing perfect
mustn't I have been speculating? mustn't you have been speculating? mustn't he have been speculating? mustn't we have been speculating? mustn't you have been speculating? mustn't they have been speculating?