Помогите, пожалуйста, с 3 или 4 номером, заранее спасибо.

Ответ:

yet,since,still,yet, already,still,just,for.

1. How long have you studied English?

2.I haven't visited the USA yet.

3.He has just given interview.

4.They have lived in Canada since 2015.

5I still haven't met your brother.

6.They have lived for twenty years here.