单选题 I have no doubt ______ he will overcome all his difficulties.
【正确答案】 C
【答案解析】[解析] I have no doubt意为“我相信,我确信”,其后接的是同位语从句,因此应用that来引导;I have doubt意为“我怀疑”,后接同位语从句时,应用whether来引导。故选C。