如果某一总分类科目所属的明细分类科目较多,可以对明细分类科目进一步分级设置二级科目或三级科目等。( )
参考答案:对
He always brings me a pretty gift ____ he comes to visit me. [ ]
A. by the time
B. sometimes
C. every time
D. at times
超文本采用______的网状结构来组织信息。