Question

--- Where is your great-grandmother __________ your mother’s side from?
--- She is from Beijing．

A．by

B．on

C．at

D．of

Answer 1

B

解析试题分析：Family of grandmother and grandfather on mother's side指“外祖父，外祖母”，句意：--你外祖母从什么地方来？--她来自北京。By“通过”，at“在…地方”，of“…的”，都不能用于这个词组。选B。
考点：考查介词辨析