Here are the suggested words for each gap:

(1) "was"
(2) "just"
(3) "about"
(4) "on"
(5) "in"
(6) "at"
(7) "to"

The completed text would read as follows:

Diana: Hello, is that Jenny? I'm bored (1) **was** watching TV and I felt (2) **just** a chat. What are you doing?
Jenny: Hi, Diana. Well, I'm reading a book (3) **about** a Russian writer. It's (4) **on** how to become a great actor.
Diana: Really? Oh, I'm really interested (5) **in** acting. Tell me about it.
Jenny: He says it takes a long time to get good (6) **at** acting. To become popular (7) **to** the public, you need to really understand people.
Diana: That sounds just like me! Tell me more. What else does he say?