The best way to get a serious point without causing offense is humour.
A. across; with
B. out; within
C. across; in
D. down; by
网友回答
(答案→)A. across; with
B. out; within
C. across; in
D. down; by
解析：考查动词及介词的区别。get sth across “使明白，理解”；with +名词做表语或状语，with humour，是幽默的意思；句意：明白一个严肃观点最好的方法就是没有引起冒犯的情况下是有幽默的。故A 正确。