比较下面3个化合物PC,正丁醇—乙酸—水(4:1:1)展开时,Rf值由大到小的次序 发布时间:2017-04-19 06:05 │ 来源:www.tikuol.com 题型:问答题 问题: 比较下面3个化合物PC,正丁醇—乙酸—水(4:1:1)展开时,Rf值由大到小的次序
题型:问答题 I would have called you up for help had it been possible, but I ____ your phone number then.A. hadn't had B. didn't have C. shouldn't have D. couldn't have 查看答案
题型:问答题 下列各项中,关于银行结算方式的说法正确的有______。A.X企业和Y企业商品买卖,想要先收款后发货,可以选择银行本票B.X企业和Y企业同城,可以选择银行本票C.X企业和Y企业商品买卖,如果双方约定延期付款,可以选择商业汇票D.X企业和Y企业同城,可以选择商业汇票 查看答案