I must obstruct you must obstruct she must obstruct we must obstruct you must obstruct they must obstruct
V-ing form
I must be obstructing you must be obstructing she must be obstructing we must be obstructing you must be obstructing they must be obstructing
Perfect
I must have obstructed you must have obstructed she must have obstructed we must have obstructed you must have obstructed they must have obstructed
V-ing perfect
I must have been obstructing you must have been obstructing she must have been obstructing we must have been obstructing you must have been obstructing they must have been obstructing
Negation
Simple form
I must not obstruct you must not obstruct she must not obstruct we must not obstruct you must not obstruct they must not obstruct
V-ing form
I must not be obstructing you must not be obstructing she must not be obstructing we must not be obstructing you must not be obstructing they must not be obstructing
Perfect
I must not have obstructed you must not have obstructed she must not have obstructed we must not have obstructed you must not have obstructed they must not have obstructed
V-ing perfect
I must not have been obstructing you must not have been obstructing she must not have been obstructing we must not have been obstructing you must not have been obstructing they must not have been obstructing
Interrogative form
Simple form
must I obstruct? must you obstruct? must she obstruct? must we obstruct? must you obstruct? must they obstruct?
V-ing form
must I be obstructing? must you be obstructing? must she be obstructing? must we be obstructing? must you be obstructing? must they be obstructing?
Perfect
must I have obstructed? must you have obstructed? must she have obstructed? must we have obstructed? must you have obstructed? must they have obstructed?
V-ing perfect
must I have been obstructing? must you have been obstructing? must she have been obstructing? must we have been obstructing? must you have been obstructing? must they have been obstructing?
Interro-negative form
Simple form
must I not obstruct? must you not obstruct? must she not obstruct? must we not obstruct? must you not obstruct? must they not obstruct?
V-ing form
must I not be obstructing? must you not be obstructing? must she not be obstructing? must we not be obstructing? must you not be obstructing? must they not be obstructing?
Perfect
must I not have obstructed? must you not have obstructed? must she not have obstructed? must we not have obstructed? must you not have obstructed? must they not have obstructed?
V-ing perfect
must I not have been obstructing? must you not have been obstructing? must she not have been obstructing? must we not have been obstructing? must you not have been obstructing? must they not have been obstructing?