题目

—Is this the first time that youNanchang? —No. But it has been 3 years since I last here. A . visit; come B . have visited; came C . visited; came D . have visited; come 答案：B某小组开展研究性学习，在网上搜集了“冯国璋、段祺瑞、张作霖”图片，据此判断他们研究的主题是A.军阀割据B.北伐战争C.实现共和D.师夷长技