大肠杆菌分裂一代需要的时间() A.18小时 B.20分钟 C.72小时 D.60分 发布时间:2017-06-11 02:50 │ 来源:www.tikuol.com 题型:单项选择题 问题: 大肠杆菌分裂一代需要的时间()A.18小时B.20分钟C.72小时D.60分钟E.20秒
题型:单项选择题 John and I _____ friends for eight years. We first got to know each other at a Christmas party. But we _____ each other a couple of times before that.A.had been; have seen B.have been; have seen C.had been; had seen D.have been; had seen 查看答案