---Sometimesstudentsmayhave________themselves.---Let'sseewhatwecando

---Sometimes students may have ________ themselves.---Let's see what we can do to help them.A.difficulty expressingB.difficulty to expressC.difficulties in expressingD.difficulties express

A解析difficulty可用作可数名词，如本练课本中：I seldom have any difficulties. 但在固定的句式或短语中要遵循惯用法．

我明天再问问老师，叫他解释下这个问题