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