A:系统性红斑狼疮
B:获得性免疫缺陷综合症
C:过敏反应
D:感染引起的关节炎
What would ____(your/you)like?
My father likes art and he often ________ in his free time.
设a∈R,则“a=1”是“直线l1:ax+2y-1=0与直线l2:x+a+1y+4=0平行”的( )