Need既可做情态动词,也可做行为动词.
Need I go to get the umbrella for you? 我需要帮你带上雨伞吗?这里Need做情态动词用.
做行为动词用的时候,用法跟其他动词一样,变疑问句,要加动词do. Does the bike need repairing? 这辆自行车需要修理吗?