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