.The researcher is so designed that once ________ nothing can be done to change itA.begins B.having begun D.beginning D.begun

.The researcher is so designed that once ________ nothing can be done to change itA.begins B.having begun D.beginning D.begun
.The researcher is so designed that once ________ nothing can be done to change it
A.begins B.having begun D.beginning D.begun

.The researcher is so designed that once ________ nothing can be done to change itA.begins B.having begun D.beginning D.begun
D.
此题是2002年全国高考卷里的一道题,考查过去分词的用法.有人早就解释过了.我也再做点解释.
在 so ...that ...结果状语从句里面,once begun 是过去分词作状语,相当于状语从句 once it is begun,“一旦它被启动了,被开始了”.所以,begun 是过去分词作状语,正确答案选 D.

B

D 一旦开始……是过去分词做状语

考查非谓语动词，排除A. D. 又因为没强调时间，所以选择beginning. C