if you sing songs ___a living ,your job will sometimes be very exciting.
问题描述：
if you sing songs ___a living ,your job will sometimes be very exciting.
A for B at C by D of 为什么?作出分析
答
答案：选A for ,表唱歌的目的.
译全句
if you sing songs ___a living ,your job will sometimes be very exciting
for a living:生活,以...谋生
如果你唱歌（ 谋生 ）,你的工作有时会很兴奋.
B at,没有这种表达方式,排除
C by,表方式 ,由...,显然符逻辑,排除
D of,所有格,...的,排除.
例：
Man should work for a living.
人应该为谋生而工作