UC知道The reserch is so designed that once ___ nothing can be done to change it.
来源：百度知道 编辑：UC知道 时间：2024/09/21 22:36:54
The reserch is so designed that once ___ nothing can be done to change it.
A.begins B.having begun C.beginning D.begun
为什么选D？
A.begins B.having begun C.beginning D.begun
为什么选D？
research 被动begin: that once (省略了the research is) begun nothing can be done to change it.
从句是过去时 所以要用begun 这个过去式
一般过去时表被动，一旦开始就无法改变。
begun (having been begun) 形容 the research