Fill in the gaps with the correct realtive pronoun or adverb and say if they can be omitted or not.
1. Robert is a boy whose dream is to become a famous dancer (cannot be omitted)
2. That's the reason ______ he works so much.
3. Each year he wins contests ________ are very important for his emerging career.
4. The moment ______ I met him is a moment I will never forget.
5. He is someone ______ I will always admire for his ambition.
6. That's the reason __________ I met him whenever I have the change.
7. They are very good friends, _________ understand and appreciate each other.​