assert，affirm，maintain

assert宣称、断言，常指某人主观自信，坚持己见，有时不顾客观事实而断言下结论。
affirm指以事实为依据，深信不疑地肯定某种观点或看法。
maintain指在相反的证据或论点面前，重申原来的某种观点、立场。

[practise]: A．Despite all the policeman’s questions the suspect ＿＿＿ that he had been at home all evening． 
B．It is nonsense to ＿＿＿ that smoking does not damage people’s health． 
C．Throughout his prison sentence Dunn has always ＿＿＿ his innocence． 
Answers：A.affirmed B.assert C.maintained