They often resort to listening Emo music as a release or escape but little ______ they know that it would just make matters worse.

【正确答案】 D

【答案解析】 当否定副词little置于句首时，句子要用部分倒装形式。but连接的两个并列句，不分时间先后，所以应该用一般现在时态。故答案为D。