Respuesta:
1) a. have you ever ridden...
b. have flyed
2) a. has never been...
b. has been
3) a. have you done...
b. have swum .... we have climbed
4) b. haven't seen...
5) a. have they reached...
b. have just arrived
6) a. has he been...
b. has travelled
7) a. have you heard...
b. has been
