Parents should pay attention to areas their child is having difficulty and spend extra time to help him or her master those skills.
A. as
B. where
C. why
D. when
网友回答
A. as
(答案→)B. where
C. why
D. when
解析：考查定语从句，先行词是areas，定语从句中缺少地点状语，用where，句意是：父母应该注意孩子有困难的地方，额外花时间帮助他们掌握这些技能。选B。