The Passive Tense

We use the passive tense when we don´t know who is doing the action.  When using the passive tense, it is not important or not known, who or what is performing the action.

Example: Fish robots are produced in Japan.  Think about what is the verb.  Produced.  Produced is the participle of produce.  Produce, produced, produced.
In this sentence, we do not know who produced the fish robots.  So we use the passive (the participle verb).

Form of Passive

Subject + finite form of to be + Past Participle (3rd column of irregular verbs)

Example: Oranges are grown in Spain.  Coffee is grown in Brazil.
Grow, grew, grown.

Practice using the passive tense in the link below!  Good luck!

https://www.ego4u.com/en/cram-up/grammar/passive/exercises