Jawaban:

1. those dishes had been washed before my mom arrived (passive)

piring-piring itu sudah dicuci sebelum ibuku datang (pasif)

My brother had washed those dishes before my mom arrived (active)

Adikku sudah mencuci piring itu sebelum ibuku datang (aktif)

2. the dress will be being delivered tomorrow (passive)

gaun akan dikirim besok (pasif)

The courier will deliver the dress tomorrow (active)

Kurir akan mengirimkan gaun itu besok (aktif)

Penjelasan:

The Simple Future Tense in the Active Voice:

Subject + will + verb (base form) + object

The Simple Future Tense in the Passive Voice:

Object + will + be + verb (past participle form) + by + subject