Question

training is worthless unless there is proof that

training is worthless unless there is proof that it works.除非能证明训练有效,否则就是白搭。我的翻译是训练是无效的否则就能证明他有用，不太理解这种语法，该怎么分析这句话的语法

Answer 1

Training is worthless unless there is proof that it works 是原意的反译，属于一种变通翻译手段。这是多重复合句，其结构是：

〔主句〕training is worthless
〔条件状语从句〕unless there is proof that it works （that is works 是嵌套的定语从句）

也可以翻译为 It is fruitless only when training is not proved effective，这也是一种反译的方法。

Answer 2

unless是引导条件状语从句的连词，意思是''如果不，除非''
本句中的that从句是同位语从句。
本句可以翻译为：如果不能证明训练有用，训练则毫无价值。
下面四句意思是一样的。
training is worth if there is proof that it works.
training is worth unless there is proof that it doesn't work.
training is worthless unless there is proof that it works.
training is worthless if there is proof that it doesn't work.

Answer 3

除非能证明训练有效，否则它没有意义

Answer 4

training is worthless unless there is proof that it works
unless直接替换成 if not
training is worthless if not there is proof that it works
将not后置 training is worthless if there is not proof that it works
这样是不是就很清楚了
1.training is worthless
2.there is not proof （that it works） 此处that it works修饰proof
if连词连接两句话