题目

–These farmers have been to the United States.    –Really? When ____ there?         A. will they go      B. did they go   C. do they go       D. have they gone 答案：B“秀才不出门，便知天下事”这一说法变成今天的现实主要得益于哪一高科技领域的巨大成就 [     ]A．激光技术            B．生物技术C．航天技术            D．信息技术