亚洲的居民以____ 人种为主。
读“宗教景观图”,与其宗教对应正确的是( )
You'd better ask a ______, such as your aunt or sister, to look after your children while you are away.
如果复数2+ai1+2i的实部和虚部互为相反数,那么实数a等于 ( )