I must abstain you must abstain he must abstain we must abstain you must abstain they must abstain
V-ing form
I must be abstaining you must be abstaining he must be abstaining we must be abstaining you must be abstaining they must be abstaining
Perfect
I must have abstained you must have abstained he must have abstained we must have abstained you must have abstained they must have abstained
V-ing perfect
I must have been abstaining you must have been abstaining he must have been abstaining we must have been abstaining you must have been abstaining they must have been abstaining
Negation
Simple form
I must not abstain you must not abstain he must not abstain we must not abstain you must not abstain they must not abstain
V-ing form
I must not be abstaining you must not be abstaining he must not be abstaining we must not be abstaining you must not be abstaining they must not be abstaining
Perfect
I must not have abstained you must not have abstained he must not have abstained we must not have abstained you must not have abstained they must not have abstained
V-ing perfect
I must not have been abstaining you must not have been abstaining he must not have been abstaining we must not have been abstaining you must not have been abstaining they must not have been abstaining
Interrogative form
Simple form
must I abstain? must you abstain? must he abstain? must we abstain? must you abstain? must they abstain?
V-ing form
must I be abstaining? must you be abstaining? must he be abstaining? must we be abstaining? must you be abstaining? must they be abstaining?
Perfect
must I have abstained? must you have abstained? must he have abstained? must we have abstained? must you have abstained? must they have abstained?
V-ing perfect
must I have been abstaining? must you have been abstaining? must he have been abstaining? must we have been abstaining? must you have been abstaining? must they have been abstaining?
Interro-negative form
Simple form
must I not abstain? must you not abstain? must he not abstain? must we not abstain? must you not abstain? must they not abstain?
V-ing form
must I not be abstaining? must you not be abstaining? must he not be abstaining? must we not be abstaining? must you not be abstaining? must they not be abstaining?
Perfect
must I not have abstained? must you not have abstained? must he not have abstained? must we not have abstained? must you not have abstained? must they not have abstained?
V-ing perfect
must I not have been abstaining? must you not have been abstaining? must he not have been abstaining? must we not have been abstaining? must you not have been abstaining? must they not have been abstaining?