单选题 Is x less than y ?(1) x-y+1<0(2) x-y-l<0
【正确答案】 A
【答案解析】Determine if x < y is true.(1) If x-y+ 1 < 0, then x < 1 and x < y is true. However, if x = 1.5 and y=1,then x- y- 1 = -0.5 < 1 and x < y is not true; NOT sufficient.The correct answer is A; statement 1 alone is sufficient.