一道高三英语时态题Chinese citizens ____ the largest group of immigran
一道高三英语时态题
Chinese citizens ____ the largest group of immigrants to Australia,
taking place of the traditional sources of Britain and New Zealand.
A.is becoming B.was becoming C.became D.had become
为什么不能选A?“正在成为”不行吗?题目里并没有关于时间的限制啊