有一对兔子，从出生后第3个月起每个月都生一对兔子，小兔子长到第三个月 　　　后每个月又生一对兔子，假如兔子都不死，问每个月的兔子总数为多少？-A pair of rabbits every month from 3 months after birth, gave birth to a pair of rabbits, rabbits grow to three months After a month gave birth to a pair of bunny rabbit