According to text 4,

Text 4 (for questions 42, 43, 44, 45, and 46)

                                                                       Social networks

Going into the small room at the end of the corridor, Roberta sat down _______ ¹ the computer. It was the computer she had bought when her old one’s hard disk had started to go wrong. Her new computer was a laptop with a lot of extra features and she needed it for her online work _______ ² her students. Roberta had started to worry that her students would be bored unless she used modern technology in her teaching.

She turned_______ ³ the switch at the back of her computer. She looked at the email messages waiting for her answer, but she ignored them. Then she looked at the homework posted on a special site she created for the students, but she didn’t feel like correcting it. Instead she went to her favorite social network site and looked at the news about her friends. She sent messages to her favorite people and she had many online conversations _______ ⁴ teaching and other things. She posted some new messages on her own web page and then watched a film clip on a video site which her friend had told her about.

_______ ⁵ now, it was late and she realized that she had spent too much time talking to her friends online. She was very tired. She would have to do all her work in the morning.

(HARMER, J. Essential Teacher Knowledge: core concepts in English language teaching, p. 42. Harlow: Pearson Education Limited, 2012. Adaptado.)