“sweat blood”别理解成“血汗”。真实含义是呕心沥血；竭尽全力；拼命工作。

【例句】
I sweat blood for five years, and he corrects my spelling.
我呕心沥血地写了五年，他来校正一下拼写。

They are all sweat blood to get the work finished before friday.
为了赶在星期五前完成，他们都在拼命做。