1.
1) already
2) yet
3) never
4) just
5) before
2.
1) Have you ever met a postcard?
2) Has your teacher been to England?
3) They have never ridden on a rollercaster.
4) My best friend has never been to Italy.
5) Have you ever explored a haunted mansion?
6) Has he ever visited The Great Wall of Chine?
7) I have never flown in a helicopter.