【题目】Having watched TV for too long, I felt it boring.
→Having watched TV for too long, I it.

【答案】was；tired；of
【解析】句意：看电视时间太长，我厌倦了。be tired of固定短语，“厌倦”，根据I felt it boring的时态是一般过去时，因此答案为was，tired ，of。