题目

   He had just lost his job when, at the precise moment, his girlfriend broke up with him. She ____ salt into his wound.         A. rubbed       B. had rubbed      C. would rub       D. was rubbing 答案：D促使我国古代农业从集体耕种向个体农耕转变的最重要因素是（  ）A．生产工具的改进B．自然环境的变化C．耕作经验的丰富D．劳动者素质的提升