Interrogative: 1) Who lives in Europe? 2) Who decided to go to Africa?
General: 1) Do they live in Europe? 2) Did she decide to go to Africa?
Special: 1) Where do they live? 2) Where did she decide to go to?
Alternative: 1) Do they live in Europe or in Asia? 2) Did she decide to go to Africa or to the USA?
Tag: 1) They live in Europe, don't they? 2) She decided to go to Africa, didn't she?