We are sure that ________to do this face to face, he would find it difficult to express himself without losing his temper.
句意:我们确信如果他尝试面对面,他会发现很难在表达想法时不发脾气。 that从句中含有虚拟语气(对将来的虚拟),即:If he were to try to do this face to face。if 从句中如果含had,were,should时,可将它们提前,省略if。因此,本题的正确答案为 A。