Jawaban:

1. Letters aren't written by most people now.
2. Some food can be made by us for the workshop.
3. Their letters weren't kept by them for the grandchildren.
4. Students are taught to work in a team.
5. English must be spoken by the students in this class.

Penjelasan:

Kalimat pasif atau passive voice digunakan untuk menunjukkan ketertarikan pada seseorang atau objek yang dikenai tindakan dan bukan seseorang atau objek yang melakukan tindakan. Jadi, hal atau orang yang terpenting akan menjadi subjek kalimat.

Rumus:

1 & 4. Simple Present Tense

• (+) S + V1 + OmenjadiO + to be (am, is, are) + V3 + by + S.
• (-) S + don't/doesn't + V1 + OmenjadiO + to be (am not, isn't, aren't) + V3 + by + S.

2 & 5. Modals

• S + modal (can, must) + V1 + OmenjadiO + modal (can, must) + be + V3 + by + S.

3. Simple Past Tense [Negative Form]

• S + didn't + V1 + OmenjadiO + to be (wasn't, weren't) + V3 + by + S.

Semoga membantu, jadikan jawaban yang terbaik ya ^.^