It depends on the context - can you provide some more information?

Which sentence is correct: 1. I thought you WERE WORKING in the office this week. (correct) Here, you are using the past continuous tense to describe an "uninterrupted" event taking place over a duration in the past. For example, it is now Saturday, and you thought someone was working earlier in the week from Monday to Wednesday. 2. I thought you HAD WORKED in the office this week. (correct as well) The past perfect tense is used to talk about something that happened (an earlier event) before something else (a more recent event) in the past. For example, it is now Monday. Last Friday, you thought of your friend and believed that he had done his work last Monday. I hope this helps.

оба правильные, но выражают разные события выбор зависит от того, какую грамматическую тему изучаете

They are both correct depending on the context they're being used. I thought you were working in the office this week - sounds like the speaker is unsure of where the worker was supposed to be working and the work to be performed is continuous. I thought you had worked in the office this week - sounds like the week is over and the speaker is confused as to where the worker was or perhaps the worker was not honest about their whereabouts.

well the first one is not completely in the past because it is continuous* but the second already happened so the week that you thought he worked in the office ended. so it depends on the context!