The most destructive element in the human mind is fear．Only when we are no longer afraid to live．
A. we are beginning
B. begin we
C. we begin
D. do we begin
网友回答
A. we are beginning
B. begin we
C. we begin
(答案→)D. do we begin
解析：考查only的倒装句：only后面接状语，如副词，介词短语，状语从句，后面的主句是部分倒装，助动词，be动词或情态动词要放在主语前面，句意：人类大脑中最致命的是恐惧，只有当我们不再害怕了，我们才能开始生活。选D。