Choose the correct options to complete the sentences

1. I am afraid that we've
   [yet|already|never] missed the plane.
2. Jack doesn't go to school. He has the flu
   [since|for|just] a week now.
3. He has
   [ever|never|just] ridden a camel in his life.
4. Many people haven't been abroad
   [since|for|yet] 2020.
5. She hasn't volunteered for the charity organisation [already|yet|since].