题目

It seems hard to watch someone yawn（打哈欠） and not to yawn ourselves. Even reading about yawning can make you do it. Now, a new study has found why yawning has such a powerful force.      Yawning when others yawn, the study suggests, is a sign of pity and a form of social connection. Kids don’t develop this deeply rooted behavior until around age four, the study found. Kids with autism (自闭症) are less likely to catch yawns. In the most serious cases, they never do. Yawning might help doctors to see whether the children are developing rightly. The work could also lead已知二次函数的图象的对称轴为x=2,函数的最小值为3,且图象经过点(- 1,5),求此二次函数图象的关系式