i think ___right to tell him the truth

i think ___right to tell him the truth I was demanded to tell him the truth. I want to tell him the truth .改成否定句 I think ( )necessary to tell you the truth I shall tell him the truth,______ . i'm telling him the truth i'll tell him the truth 能不能把 to tell you the truth, I don't believe him.改成 telling y to tell you the truth,I don't believe him.中的不定式做什么成分 i have had to tell the truth I had to tell the truth .___I tell the truth about him I think he is pretty bold, to tell you the truth．