Ответ:

Перевод задания: Прочитайте текст. Из каждой строки (B12–B21) выпишите одно лишнее слово.

Лишние слова по порядку: B12 — when; B13 — One; B14 — a; B15 — itself; B16 — much; B17 — which; B18 — such; B19 — to; B20 — enough; B21 — be.

После удаления лишних слов получается связный текст:

Kara has an unusual job. During the week she is a student at university, but at weekends she is a mystery shopper. What does this mean? Day she buys a bottle of perfume, another day she goes for a meal at a restaurant. She fills in a form about the shop or restaurant and a report is sent to the company’s office. This is how the shop or restaurant gets suggestions about how they could improve to keep customers happy. It’s the perfect job for me, explains Kara. ‘It’s nice to eat in elegant restaurants from time to time as I don’t have much money for food’. The company that employs Kara says mystery shoppers must actually be reliable, have a good memory and they must be honest. If mystery shoppers tell a lie or exaggerate, we won’t use them again, explains one of the company’s managers.

Примечание: В строке B13 после удаления One остаётся грамматически странное Day she buys; вероятно, в исходном упражнении имеется опечатка или смещение строки. По видимому тексту однозначно определить корректное лишнее слово в этой строке нельзя.