I must surface you must surface she must surface we must surface you must surface they must surface
V-ing form
I must be surfacing you must be surfacing she must be surfacing we must be surfacing you must be surfacing they must be surfacing
Perfect
I must have surfaced you must have surfaced she must have surfaced we must have surfaced you must have surfaced they must have surfaced
V-ing perfect
I must have been surfacing you must have been surfacing she must have been surfacing we must have been surfacing you must have been surfacing they must have been surfacing
Negation
Simple form
I mustn't surface you mustn't surface she mustn't surface we mustn't surface you mustn't surface they mustn't surface
V-ing form
I mustn't be surfacing you mustn't be surfacing she mustn't be surfacing we mustn't be surfacing you mustn't be surfacing they mustn't be surfacing
Perfect
I mustn't have surfaced you mustn't have surfaced she mustn't have surfaced we mustn't have surfaced you mustn't have surfaced they mustn't have surfaced
V-ing perfect
I mustn't have been surfacing you mustn't have been surfacing she mustn't have been surfacing we mustn't have been surfacing you mustn't have been surfacing they mustn't have been surfacing
Interrogative form
Simple form
must I surface? must you surface? must she surface? must we surface? must you surface? must they surface?
V-ing form
must I be surfacing? must you be surfacing? must she be surfacing? must we be surfacing? must you be surfacing? must they be surfacing?
Perfect
must I have surfaced? must you have surfaced? must she have surfaced? must we have surfaced? must you have surfaced? must they have surfaced?
V-ing perfect
must I have been surfacing? must you have been surfacing? must she have been surfacing? must we have been surfacing? must you have been surfacing? must they have been surfacing?
Interro-negative form
Simple form
mustn't I surface? mustn't you surface? mustn't she surface? mustn't we surface? mustn't you surface? mustn't they surface?
V-ing form
mustn't I be surfacing? mustn't you be surfacing? mustn't she be surfacing? mustn't we be surfacing? mustn't you be surfacing? mustn't they be surfacing?
Perfect
mustn't I have surfaced? mustn't you have surfaced? mustn't she have surfaced? mustn't we have surfaced? mustn't you have surfaced? mustn't they have surfaced?
V-ing perfect
mustn't I have been surfacing? mustn't you have been surfacing? mustn't she have been surfacing? mustn't we have been surfacing? mustn't you have been surfacing? mustn't they have been surfacing?