The word 'however' is a conjunction used to introduce a contrast or a contradiction to what was previously stated. It signals a shift in direction or a contrasting idea. * **Core Concept:** Understanding the function of contrastive conjunctions. * **Solution Analysis:** The correct answer (B) accurately describes the function of 'however'. * **Detailed Option Analysis:** * **A:** Incorrect. 'However' doesn't introduce supporting ideas. * **B:** Correct. 'However' introduces a contrasting idea. * **C:** Incorrect. 'However' does not provide examples. * **D:** Incorrect. 'However' does not introduce cause-and-effect relationships. * **Common Mistakes:** Confusing 'however' with conjunctions like 'therefore' or 'for example'.