Hi Anna The sentence is OK, but for one week it is usually expressed slightly differently, depending on what you are trying to say. Here are some examples, all with similar meaning: I was back at work a week ago I was back at work last week I went back to work a week ago I went back to work last week I came back to work last week I have been back at work for a week I have been back at work since last week For more than one week, simply use 'xx weeks ago' or 'for xx weeks' instead.

The sentence "I was back at work 1 week ago" is correct. If you were in an English class, the teacher might ask that you spell out "1" (one). The phrase between the "()", is incorrect. It should be "is this sentence correct?"