Summary: ``In the present paper, we mainly discuss the $(\bot,\top)$-generalized fuzzy rough sets introduced by B. Q. Hu and Z. H. Huang with both constructive approach and axiomatic approach considered. In the former, we started from the investigation of the properties of the $\bot$-upper and $\top$-lower approximation operators generated by binary fuzzy relations. In the latter, by defining a pair of fuzzy set-theoretic operators, we show $(\bot,\top)$-fuzzy rough approximation operators can be characterized by different sets of axioms.''