1) If in active verb construction the verb is in Imperfective aspect (IPFV), then in order to form passive you need to add -СЯ at the end of IPFV verb.
Activ = IPFV | Passive = IPFV + СЯ |
Люди исследуют (IPFV) космос.
People are exploring space. Люди исследовали (IPFV) космос. People explored space. Люди будут исследовать (IPFV) космос. People will explore space. | Космос исследуется людьми.
Space is being explored by people. Космос исследовался людьми. Space was explored by people. Космос будет исследоваться людьми. Space will be explored by people |
2) If in active verb construction the verb is in Perfective aspect (PFV), then in order to form passive you need to change a verb to short form participle.
Activ = PFV
| Passive = short form participle
|
Я испекла (PFV) пирог
I baked a pie. Я испеку (PFV) пирог. I will bake a pie. | Пирог (был) испечён мной.
A pie was baked by me. Пирог (будет) испечён мной. A pie will be baked by me. |