Eg:The research is so designed that once_____ nothing can be done_英语解答

Eg:The research is so designed that once_____ nothing can be done to change it.A begins B
having begun C begining D begun.Why choose

人气：260 ℃　时间：2019-10-26 05:13:00

解答

原因是横线上本来是一个省略句,句子本身是【once it's begun】一旦研究被开始
由于主语是it+be+过去分词的形式,因此可以省略剩下过去分词【begun】
翻译：这项研究设定好了,一旦开始任何事情都不能去改变它.