Good technique in medicine means less pain and fewer deaths and, ________ it is our duty to master it．
A.altogetherB.thereforeC.otherwiseD.however在线课程B
本题考查副词在语言环境中的意思．句中therefore在此处表示“因此”，与as a result, so意思相近．altogether表示“总的来说”，相当于on the whole; otherwise表示“否则”，相当于or; however用作副词表示“不管如何，然而”．从全句意思看应为B项．