问题
It is not until ______ that ______.
A:is a baby kangaroo four months old he will begin to live outside its mother’s pouch
B:is a baby kangaroo four months old will he begin to live outside its mother’s pouch
C:a baby kangaroo is four months old he will begin to live outside its mother’s pouch
D:a baby kangaroo is four months old will he begin to live outside its mother’s pouch
B:is a baby kangaroo four months old will he begin to live outside its mother’s pouch
C:a baby kangaroo is four months old he will begin to live outside its mother’s pouch
D:a baby kangaroo is four months old will he begin to live outside its mother’s pouch
正确答案是：
