should witness
Regular verb: witness - witnessed- witnessed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I should witness
you should witness
she should witness
we should witness
you should witness
they should witness 	I should be witnessing
you should be witnessing
she should be witnessing
we should be witnessing
you should be witnessing
they should be witnessing	I should have witnessed
you should have witnessed
she should have witnessed
we should have witnessed
you should have witnessed
they should have witnessed	I should have been witnessing
you should have been witnessing
she should have been witnessing
we should have been witnessing
you should have been witnessing
they should have been witnessing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I should not witness
you should not witness
she should not witness
we should not witness
you should not witness
they should not witness 	I should not be witnessing
you should not be witnessing
she should not be witnessing
we should not be witnessing
you should not be witnessing
they should not be witnessing	I should not have witnessed
you should not have witnessed
she should not have witnessed
we should not have witnessed
you should not have witnessed
they should not have witnessed	I should not have been witnessing
you should not have been witnessing
she should not have been witnessing
we should not have been witnessing
you should not have been witnessing
they should not have been witnessing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
should I witness?
should you witness?
should she witness?
should we witness?
should you witness?
should they witness? 	should I be witnessing?
should you be witnessing?
should she be witnessing?
should we be witnessing?
should you be witnessing?
should they be witnessing? 	should I have witnessed?
should you have witnessed?
should she have witnessed?
should we have witnessed?
should you have witnessed?
should they have witnessed? 	should I have been witnessing?
should you have been witnessing?
should she have been witnessing?
should we have been witnessing?
should you have been witnessing?
should they have been witnessing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
should I not witness?
should you not witness?
should she not witness?
should we not witness?
should you not witness?
should they not witness? 	should I not be witnessing?
should you not be witnessing?
should she not be witnessing?
should we not be witnessing?
should you not be witnessing?
should they not be witnessing? 	should I not have witnessed?
should you not have witnessed?
should she not have witnessed?
should we not have witnessed?
should you not have witnessed?
should they not have witnessed? 	should I not have been witnessing?
should you not have been witnessing?
should she not have been witnessing?
should we not have been witnessing?
should you not have been witnessing?
should they not have been witnessing?