Today，we’ll discuss a number of cases parents have much difficulty in municating with their children.
A. which
B. as
C. why
D. where
网友回答
A. which
B. as
C. why
(答案→)D. where
解析：考查定语从句。句中先行词为cases，在定语从句中作地点状语，故用关系副词where。句意：今天，我们将讨论许多案例，在这些案例中父母与他们的孩子交流有很多的困难。故D正确。