I must forefend you must forefend he must forefend we must forefend you must forefend they must forefend
V-ing form
I must be forefending you must be forefending he must be forefending we must be forefending you must be forefending they must be forefending
Perfect
I must have forefended you must have forefended he 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 he 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 he 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 he 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 he 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 he 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 he forefend? must we forefend? must you forefend? must they forefend?
V-ing form
must I be forefending? must you be forefending? must he be forefending? must we be forefending? must you be forefending? must they be forefending?
Perfect
must I have forefended? must you have forefended? must he 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 he 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 he 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 he 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 he 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 he have been forefending? mustn't we have been forefending? mustn't you have been forefending? mustn't they have been forefending?