单选题 It is becoming (far less) common than it (was used) to be for children to (follow in) their (fathers' footsteps).
【正确答案】 B
【答案解析】将was used to改为used to。used to后接动词原形，表示“过去常常做某事”；be used to后接动词的-ing形式，表示“习惯于做某事”。