Whoran_______ of all in the sports meeting – Hector did, I think.

Today’s teens don’t see anything strange in the fact _______the computer takes up a central place in their social lives.

Are you willing to live on Mars one day –_____ It sounds exciting， but it still worries me.

“Youth” is regarded by many people as a time in their life _____ fun, passion, and imagination seem limitless.

This key ring doesn’t belong to _______, maybe it’s________.