Ответ:

1. Mr Richards, who is a taxi driver, worked here.

2. Thank you for your e-mail, which was very useful.

3. That’s Tom, the boy who has just arrived from Spain.

4. The children who shouted in the street are not from our school.

5. I live in the house, which is situated not far from the forest.

6. The National Nature Park, which I visited last month, was really great.

Объяснение:

Who — кто

Whom — кого

Whose — чей

Which — который

That — который

• Who и whom используются, когда мы говорим о людях
• Which — когда говорим о вещах
• That используется, чтобы описать и определить вещь, про которую мы уже говорили.