属于自身免疫性疾病的是
A．雪口病B．寻常狼疮C．带状疱疹D．手足口病E．寻常型天疱疮
参考答案：E
已知x1，x2是方程x2-x-1=0的两个根，则x12+x22的值为______．
It would not be________for us to attend a formal wedding with the sports clothes. [ ]
A. comfortable
B. appropriate
C. convenient
D. available
