i don't know w____it is a fast train or not

i don't know w____it is a fast train or not I don't know. “i don't know you know i don't know sorry,I don't know. i don`t know much I don't really know. 英语；I don't know I don't know miss I don't know him. I don't know now 翻译 i don't know So know,I don't I don't know her i don't know anything I know enough to know that I don't know i don't know what i I don't think I know you I don’t no I don't know