I must tremble you must tremble she must tremble we must tremble you must tremble they must tremble
V-ing form
I must be trembling you must be trembling she must be trembling we must be trembling you must be trembling they must be trembling
Perfect
I must have trembled you must have trembled she must have trembled we must have trembled you must have trembled they must have trembled
V-ing perfect
I must have been trembling you must have been trembling she must have been trembling we must have been trembling you must have been trembling they must have been trembling
Negation
Simple form
I must not tremble you must not tremble she must not tremble we must not tremble you must not tremble they must not tremble
V-ing form
I must not be trembling you must not be trembling she must not be trembling we must not be trembling you must not be trembling they must not be trembling
Perfect
I must not have trembled you must not have trembled she must not have trembled we must not have trembled you must not have trembled they must not have trembled
V-ing perfect
I must not have been trembling you must not have been trembling she must not have been trembling we must not have been trembling you must not have been trembling they must not have been trembling
Interrogative form
Simple form
must I tremble? must you tremble? must she tremble? must we tremble? must you tremble? must they tremble?
V-ing form
must I be trembling? must you be trembling? must she be trembling? must we be trembling? must you be trembling? must they be trembling?
Perfect
must I have trembled? must you have trembled? must she have trembled? must we have trembled? must you have trembled? must they have trembled?
V-ing perfect
must I have been trembling? must you have been trembling? must she have been trembling? must we have been trembling? must you have been trembling? must they have been trembling?
Interro-negative form
Simple form
must I not tremble? must you not tremble? must she not tremble? must we not tremble? must you not tremble? must they not tremble?
V-ing form
must I not be trembling? must you not be trembling? must she not be trembling? must we not be trembling? must you not be trembling? must they not be trembling?
Perfect
must I not have trembled? must you not have trembled? must she not have trembled? must we not have trembled? must you not have trembled? must they not have trembled?
V-ing perfect
must I not have been trembling? must you not have been trembling? must she not have been trembling? must we not have been trembling? must you not have been trembling? must they not have been trembling?