I must drain you must drain he must drain we must drain you must drain they must drain
V-ing form
I must be draining you must be draining he must be draining we must be draining you must be draining they must be draining
Perfect
I must have drained you must have drained he must have drained we must have drained you must have drained they must have drained
V-ing perfect
I must have been draining you must have been draining he must have been draining we must have been draining you must have been draining they must have been draining
Negation
Simple form
I must not drain you must not drain he must not drain we must not drain you must not drain they must not drain
V-ing form
I must not be draining you must not be draining he must not be draining we must not be draining you must not be draining they must not be draining
Perfect
I must not have drained you must not have drained he must not have drained we must not have drained you must not have drained they must not have drained
V-ing perfect
I must not have been draining you must not have been draining he must not have been draining we must not have been draining you must not have been draining they must not have been draining
Interrogative form
Simple form
must I drain? must you drain? must he drain? must we drain? must you drain? must they drain?
V-ing form
must I be draining? must you be draining? must he be draining? must we be draining? must you be draining? must they be draining?
Perfect
must I have drained? must you have drained? must he have drained? must we have drained? must you have drained? must they have drained?
V-ing perfect
must I have been draining? must you have been draining? must he have been draining? must we have been draining? must you have been draining? must they have been draining?
Interro-negative form
Simple form
must I not drain? must you not drain? must he not drain? must we not drain? must you not drain? must they not drain?
V-ing form
must I not be draining? must you not be draining? must he not be draining? must we not be draining? must you not be draining? must they not be draining?
Perfect
must I not have drained? must you not have drained? must he not have drained? must we not have drained? must you not have drained? must they not have drained?
V-ing perfect
must I not have been draining? must you not have been draining? must he not have been draining? must we not have been draining? must you not have been draining? must they not have been draining?