从重整汽油中提取芳烃常用（）方法。
参考答案：液液萃取
—______ did you go to Beijng with your family?
—We went there in July.[ ]
A. What
B. How
C. When
世界上火山最多的国家，有“火山国”之称是______．世界上有“花园城市”美称是______（国家）．
