题目

 Very mobile ears help many animals direct their attention to the rustle of a possible attacker. Researchers say these mobile ears have become a useful communication tool. Their studies of animal behaviour build up a picture of how communication and social skills developed.    “We're interested in how they communicate,” said lead researcher Jennifer Wathan.“And being sensitive to what another individual is thinking is a fundamental skill from which other more complex skills develop.” Ms Wathan and her colleague Prof Karen McComb set up a behavioural experiment where 72 indiv18．不等式|x-1|+|x-2|≤5的解集为[-1，4]．