A1A2A3b1
A1B2A3分别是
A1a2b1b二分别
A1a2b1B2C1c2什么
a1a2b1b2是什么
A1A2B1
A1a2B2是
a1b2c2d代表什么
A1A2A3B1B2C1c2C3C