Wasnt I tempting fate: how could these hard-nosed Nazi detectives help but smell out the diaries beneath my broadcasts?
can not help but do意思是不可防止、不由自主的做.....
但这里变成特殊疑问句，没了can not 还是那个意思吗？
翻译句子有点乱了!
Wasnt I tempting fate： how couldnt these hard-nosed Nazi detectives help but smell out the diaries beneath my broadcasts？
参考译文：我这不是在拿性命开玩笑吗？那些精明务实的的纳粹侦探如何可能嗅不出广播稿下面的日记呢？
重点短语分析
tempt fate 冒险，玩命,冒非必须的险
At the same time the State Department bureaucracy tended to tempt fate.
同时,国务院的官僚机构有铤而走险的倾向.
The bike brakes dont work. If you ride downhill， you’ll be tempting fate.
这辆自行车的闸不灵了。你如果骑它走下坡，那你就是玩儿命。
hard-nosed精明而讲究实质的，不感情用事的;坚韧的
If nothing else, Doug is a hard-nosed businessman.
别的不说，道格起码是个精明务实的商人。
We all like John; he plays hard - nosed football.
大家都爱约翰, 他踢起球来作风顽强勇猛.
My uncle was a hard - nosed army officer who had seen service in two wars.
我叔叔是位严格而又倔强的军医,他曾身经两次大战.
cant help but do sth.：不能不; 不可以不; 需要; 只好;不可防止会做……；忍不住做……
When our country calls us for help, we cant help but go.
当祖国需要大家时, 大家需要尽力.
When a close friend dies, we cant help but feel sad.
当一位亲密的朋友过世时, 大家不可以不难过.
A writer cant help but reveal himself.
一个作家在作品中,总不免要显露出一些自己的影子.
I cant help but feel sorry for him.
我只能为他感到难过.
He cant help but reject the offer if there are strings attached.
假如有附带条件，他不可能不回绝。
We couldnt help but laugh when we heard his story.
听了他的故事，大家忍不住大笑起来。分页标题#e#
smell sth./ sb. out：嗅出，嗅出; 发现;（口语）探出，
The dog smelt out drugs in the suitcase.
那狗闻出了箱子里的毒品。
He says he can smell out trouble before Itstarts.
他说他能在麻烦事儿发生之前就能知道出来.
The dog will smell out a thief.
狗会靠其嗅觉而找到贼.
Specially - trained dogs can smell out drugs.
受过特殊练习的狗能嗅出毒品.
The legendary detective is said to be able to smell out murderers.
据了解那个传奇式的侦探能嗅出杀人犯。