Change into plural / Exercise 4

Rewrite each of the following sentences, adding the word two before the noun. Change the noun to the plural, and change the verb so that it agrees with its subject. For example:
A man lives in this building.
Two men live in this building.

A woman was nominated for the position.
Two women were nominated for the position.

The teacher is here.
Two teachers are here.

1. A student is volunteering.
2. A worker was ordered to leave.
3. A farmer owns land.
4. A neighbour has telephoned us.
5. A boy met us.
6. A is studying English.
7. One of my sisters does well in school.
8. A guest has arrived early.
9. One mother was making the cake.
10. One of the students knows all the answers.
11. One is planning the party.
12. One of my brothers has difficulty understanding English at school.