–I hear your dad _____Shanghai on business. Did he fly there? –Yes, but he will be home tomorrow.
A:will go to
B:has been to
C:has gone to
①亚热带和暖温带的分界线
②半湿润和半干旱地区的分界线
③季风区和非季风区的分界线
④落叶阔叶林和常绿阔叶林的分界
下列生物体内肯定不存在A﹣T碱基对的是( )