PASSIVE VOICE

The passive voice is used when we don't know or when it's not important to know who or what performed an action.

PRESENT CONTINUOUS TENSE
The form is:
THE PRESENT CONTINUOUS TENSE OF THE VERB TO BE + THE PAST PARTICIPLE OF THE MAIN VERB
Brochures are being sent to all of the agency's custumers.

PAST CONTINUOUS TENSE
The form is:
THE PAST CONTINUOUS TENSE OF THE VERB TO BE + THE PAST PARTICIPLE OF THE MAIN VERB
Brochures were being sent to all of the agency's custumers.

PRESENT PERFECT TENSE
The form is:
THE PRESENT PERFECT TENSE OF THE VERB TO BE + THE PAST PARTICIPLE OF THE MAIN VERB
Brochures has been sent to all of the agency's custumers.

PAST PERFECT TENSE
The form is:
THE PASTPERFECT TENSE OF THE VERB TO BE + THE PAST PARTICIPLE OF THE MAIN VERB
Brochures had ben sent to all of the agency's custumers.