His photos appeared in national famous magazine at that time.
A. properly
B. fluently
C. frequently
D. sincerely
网友回答
A. properly
B. fluently
(答案→)C. frequently
D. sincerely
解析：此处properly恰当地；fluently 流利地；frequently频繁地；sincerely真诚地。句意：在那时，他的照片频繁地出现在全国著名的杂志上。根据句意选C。