题目

下列企业的性质与其他三个不同的是  A．安庆军械所    B．江南制造总局        C．福州船政局     D．上海轮船招商局 答案：DI ______ my mum cook dinner in the kitchen when the telephone ________.A. helped; was ringingB. helped; rangC. was helping; rangD. was helping; was ringing