Автор - slavshem
2. That's the woman who drives the school bus. — Identifying (not omitted)
3. My sister, who is called Sarah, is younger than I am. — NI (can be omitted)
4. The cake which was covered in chocolate was delicious. — I (если тортиков было несколько), not omitted
5. I know a boy whose mother is a builder. — I (not omitted)