A new technique out, the yields increased by 20% . A. having working B. having b

A new technique ____ out, the yields (收成) increased by 20% .

A. having working        B. having been working 

C. has worked            D. had been worked

试题答案

B

解析:

根据逗号分开可知空白处不能填入谓语动词，A项从形式上就不对，根据语境应该用现在分词的完成式，此处work out表示“产生结果；有预期的结果，发展为”例如:I wonder how their ideas worked out in practice?我很想知道他们的想法在实践中取得了什么结果。