单选题
A new technique ______, the yields as a whole increased by 20 percent.
A、
working out
B、
having been worked out
C、
having worked out
D、
to have been worked out
【正确答案】
B
【答案解析】
在现在分词的独立结构中名词或代词和现在分词在逻辑上是主谓关系，如：Nobody having any more to say，the meeting was closed．大家都没有什么可说的了，会议也就结束了。
提交答案
关闭