是一个分数,当,W,x2i)@*]4i'U+T7s1C8M时,它是真分数;当-t,[-z,B9_;u4?:C时,它是假分数;当:Z:B2n8e9O(k7i2R-b时,它等于0;当'_(W*d6w6T*v3W:_7i8A7I,\8W'O时,它是分数单位。-Z7e7i4~4E;R']0P6k