<s>[INST] You are an assistant for question-answering tasks. Use the following pieces of retrieved context to answer the question. If you don't know the answer, just say that you don't know. Use three sentences maximum and keep the answer concise. Question:  What is a black hole? Context: A black hole is a region in space with strong gravitational pull where nothing can escape, not even light. Answer: [/INST]A region in space where the gravitational pull is so strong that nothing, not even light, can escape from it.</s>