I must skip you must skip he must skip we must skip you must skip they must skip
V-ing form
I must be skipping you must be skipping he must be skipping we must be skipping you must be skipping they must be skipping
Perfect
I must have skipped you must have skipped he must have skipped we must have skipped you must have skipped they must have skipped
V-ing perfect
I must have been skipping you must have been skipping he must have been skipping we must have been skipping you must have been skipping they must have been skipping
Negation
Simple form
I must not skip you must not skip he must not skip we must not skip you must not skip they must not skip
V-ing form
I must not be skipping you must not be skipping he must not be skipping we must not be skipping you must not be skipping they must not be skipping
Perfect
I must not have skipped you must not have skipped he must not have skipped we must not have skipped you must not have skipped they must not have skipped
V-ing perfect
I must not have been skipping you must not have been skipping he must not have been skipping we must not have been skipping you must not have been skipping they must not have been skipping
Interrogative form
Simple form
must I skip? must you skip? must he skip? must we skip? must you skip? must they skip?
V-ing form
must I be skipping? must you be skipping? must he be skipping? must we be skipping? must you be skipping? must they be skipping?
Perfect
must I have skipped? must you have skipped? must he have skipped? must we have skipped? must you have skipped? must they have skipped?
V-ing perfect
must I have been skipping? must you have been skipping? must he have been skipping? must we have been skipping? must you have been skipping? must they have been skipping?
Interro-negative form
Simple form
must I not skip? must you not skip? must he not skip? must we not skip? must you not skip? must they not skip?
V-ing form
must I not be skipping? must you not be skipping? must he not be skipping? must we not be skipping? must you not be skipping? must they not be skipping?
Perfect
must I not have skipped? must you not have skipped? must he not have skipped? must we not have skipped? must you not have skipped? must they not have skipped?
V-ing perfect
must I not have been skipping? must you not have been skipping? must he not have been skipping? must we not have been skipping? must you not have been skipping? must they not have been skipping?