∵x＜0,z＜0,|z|＞|x|,∴x＞z,x+z＜z＜x＜0,∵x＜0,y＞0,所以y＞x,∵x＜0,y＞0,|y|＞|x|,∴x+y＞0,但y＞x+y,
∴y＞x+y＞x＞z＞x+z