题目

_____ is know to all, china will be an________ and powerful country in 20 or 30 year’ time. A. That, advancing                 B. This ,advanced C. As, advanced                    D. It, advanced   答案：Cadvanced过去分词作定语,as引导非限制性定语从句。  基因A、a和基因B、b分别位于不同对的同源染色体上，一个亲本与aabb测交，子代基因型为AaBb和Aabb，分离比为1：l，则这个亲本基因型为                  （   ） A．AABb                                    B．AaBb C．AAbb                                    D．AaBB