How do you use the past participle become in a sentence?

The past participle of "become" is "become" itself. It's used in a few different ways:

1. As part of the passive voice:

* The house was become a museum. (This is the passive voice, meaning the house is the subject of the action, not the doer of the action.)

2. In perfect tenses:

* He has become a successful writer. (This uses the present perfect tense.)

* They had become friends before they started working together. (This uses the past perfect tense.)

3. As an adjective:

* The once vibrant city had become a desolate wasteland. (Here, "become" describes the city's state.)

Note: While "became" is the past tense of "become," "become" is the past participle.

Let me know if you'd like more examples!