Question: how to use obwohl in a sentence?
Answer: Or, more reasonably as chirlu pointed out, it emphasises that she is really ill, even though her not staying in bed might indicate that she is not. Obwohl ich krank bin, bin ich in die Schule gekommen. / Ich bin in die Schule gekommen, obwohl ich krank bin. Ich bin in die Schule gekommen, trotzdem bin ich krank.