must countersink
Verbe irrégulier : countersink - countersank- countersunk

Affirmation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I must countersink
you must countersink
he must countersink
we must countersink
you must countersink
they must countersink 	I must be countersinking
you must be countersinking
he must be countersinking
we must be countersinking
you must be countersinking
they must be countersinking	I must have countersunk
you must have countersunk
he must have countersunk
we must have countersunk
you must have countersunk
they must have countersunk	I must have been countersinking
you must have been countersinking
he must have been countersinking
we must have been countersinking
you must have been countersinking
they must have been countersinking	

Négation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I must not countersink
you must not countersink
he must not countersink
we must not countersink
you must not countersink
they must not countersink 	I must not be countersinking
you must not be countersinking
he must not be countersinking
we must not be countersinking
you must not be countersinking
they must not be countersinking	I must not have countersunk
you must not have countersunk
he must not have countersunk
we must not have countersunk
you must not have countersunk
they must not have countersunk	I must not have been countersinking
you must not have been countersinking
he must not have been countersinking
we must not have been countersinking
you must not have been countersinking
they must not have been countersinking	

Forme interrogative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
must I countersink?
must you countersink?
must he countersink?
must we countersink?
must you countersink?
must they countersink? 	must I be countersinking?
must you be countersinking?
must he be countersinking?
must we be countersinking?
must you be countersinking?
must they be countersinking? 	must I have countersunk?
must you have countersunk?
must he have countersunk?
must we have countersunk?
must you have countersunk?
must they have countersunk? 	must I have been countersinking?
must you have been countersinking?
must he have been countersinking?
must we have been countersinking?
must you have been countersinking?
must they have been countersinking? 	

Forme interro-négative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
must I not countersink?
must you not countersink?
must he not countersink?
must we not countersink?
must you not countersink?
must they not countersink? 	must I not be countersinking?
must you not be countersinking?
must he not be countersinking?
must we not be countersinking?
must you not be countersinking?
must they not be countersinking? 	must I not have countersunk?
must you not have countersunk?
must he not have countersunk?
must we not have countersunk?
must you not have countersunk?
must they not have countersunk? 	must I not have been countersinking?
must you not have been countersinking?
must he not have been countersinking?
must we not have been countersinking?
must you not have been countersinking?
must they not have been countersinking?