题目

在两对等位基因自由组合的情况下，F1自交后代的性状分离比是12∶3∶1，F1测交后代的性状分离比是( ) A．1∶3     B．3∶1 C．2∶1∶1                      D．1∶1   答案：C   My elder brother has gone to Tibet to work as a volunteer teacher．Influenced by him, I also want to become _________ when I graduate from the university． [　　] A． that B． it C． this D． one