请帮忙选一下,并说明理由,谢谢
68. A new technique ______ , the yields as a whole increased by 20 per cent. A)working out B) having worked out C)having been worked out D)to have been worked out
68. A new technique __C)having been worked out ____ , the yields as a whole increased by 20 per cent. A)working out B) having worked out D)to have been worked out technique 做逻辑主语， 应该用完成被动式，
答：A there being a chance 是 there be +...结构的变形,分词形式作为名词短语,作dreem of 的宾语 A 和D A The...详情>>
答：I haven't window molding catalogs on hand. catalogs 产品目录 haven't ~ something ~ o...详情>>
问：head+hand+hardworking=success 什么意思
答：head+hand+hardworking=success 脑+动手+努力工作 = 成功详情>>
