To be honest；your pronunciation is not so good.坦率地说,你的语音不咋的.
To be honest 在此句中语法术语是“独立成分”,通常表示“评论或附加说明”类似的例子：
to tell you the truth
generally speaking
judging from his appearance
等等.这种结构使用时,不必考虑非谓语动词的逻辑主语是否与句子主语一致.