原式=ab?2ba2
=2a.
故答案为:2a.
大革命时期的国民党是()四个阶级的革命联盟。
A、工人阶级
B、农民阶级
C、城市小资产阶级
D、资产阶级
E、民族资产阶级
Nowadays, doing part-time jobs has become a fashion to us students. What’s your opinion?