标题: OG12cs75 [打印本页] 作者: sevengu 时间: 2011-1-24 20:52 标题: OG12cs75 A proposal has been made to trim the horns from rhinoceroses to discourage poachers; the question is whether tourists will continue to visit game parks and see rhinoceroses after their horns are trimmed. (A) whether tourists will continue to visit game parks and see rhinoceroses after their horns are (B) whether tourists will continue to visit game parks to see one once their horns are (C) whether tourists will continue to visit game parks to see rhinoceroses once the animals’ horns have been (D) if tourists will continue to visit game parks and see rhinoceroses once the animals’ horns are (E) if tourists will continue to visit game parks to see one after the animals’ horns have been oa：c 请问c中为何要用once have been done作者: orange09 时间: 2011-1-24 22:42
我觉得这个是虚拟语气~~ once在这里的意思是“一旦” 所以根据其规则需要用现在完成时。。。