简述胎座及其类型

A. First grade.
B. Sixth grade.
C. Seventh grade.
D. Eighth grade.

A. Into their twenty-first.
B. Into their twenty-second.
C. Into their twenty-third.
D. Into their twentieth.

A. On her eleventh birthday.
B. On her thirteenth birthday.
C. On her tenth birthday.
D. On her twelfth birthday.