I must backstroke you must backstroke he must backstroke we must backstroke you must backstroke they must backstroke
V-ing form
I must be backstroking you must be backstroking he must be backstroking we must be backstroking you must be backstroking they must be backstroking
Perfect
I must have backstroked you must have backstroked he must have backstroked we must have backstroked you must have backstroked they must have backstroked
V-ing perfect
I must have been backstroking you must have been backstroking he must have been backstroking we must have been backstroking you must have been backstroking they must have been backstroking
Negation
Simple form
I must not backstroke you must not backstroke he must not backstroke we must not backstroke you must not backstroke they must not backstroke
V-ing form
I must not be backstroking you must not be backstroking he must not be backstroking we must not be backstroking you must not be backstroking they must not be backstroking
Perfect
I must not have backstroked you must not have backstroked he must not have backstroked we must not have backstroked you must not have backstroked they must not have backstroked
V-ing perfect
I must not have been backstroking you must not have been backstroking he must not have been backstroking we must not have been backstroking you must not have been backstroking they must not have been backstroking
Interrogative form
Simple form
must I backstroke? must you backstroke? must he backstroke? must we backstroke? must you backstroke? must they backstroke?
V-ing form
must I be backstroking? must you be backstroking? must he be backstroking? must we be backstroking? must you be backstroking? must they be backstroking?
Perfect
must I have backstroked? must you have backstroked? must he have backstroked? must we have backstroked? must you have backstroked? must they have backstroked?
V-ing perfect
must I have been backstroking? must you have been backstroking? must he have been backstroking? must we have been backstroking? must you have been backstroking? must they have been backstroking?
Interro-negative form
Simple form
must I not backstroke? must you not backstroke? must he not backstroke? must we not backstroke? must you not backstroke? must they not backstroke?
V-ing form
must I not be backstroking? must you not be backstroking? must he not be backstroking? must we not be backstroking? must you not be backstroking? must they not be backstroking?
Perfect
must I not have backstroked? must you not have backstroked? must he not have backstroked? must we not have backstroked? must you not have backstroked? must they not have backstroked?
V-ing perfect
must I not have been backstroking? must you not have been backstroking? must he not have been backstroking? must we not have been backstroking? must you not have been backstroking? must they not have been backstroking?