It is only when the stress gets out of control that it can lead to poor perf这句话的句式.It is only when the stress gets out of control that it can lead to poor performance and ill health.

It is only when the stress gets out of control that it can lead to poor perf这句话的句式.It is only when the stress gets out of control that it can lead to poor performance and ill health.
It is only when the stress gets out of control that it can lead to poor perf
这句话的句式.
It is only when the stress gets out of control that it can lead to poor performance and ill health.

It is only when the stress gets out of control that it can lead to poor perf这句话的句式.It is only when the stress gets out of control that it can lead to poor performance and ill health.
此句为It is ...that 强调句
强调的是句子的时间状语 而这里是一个从句做状语
翻译是应将it is that 去掉
强调句的基本句型为it is +被强调部分+that+其它成分
例如你要写一个强调句 只需将被强调成分放在it is .that 中间 其他照抄就行了

高手来了．
强调句型啊
与简单的强调句相比，这种句子强调的成份是一个从句．
Its　only on Monday that．．． 　强调时间状语
Its only when ... that .....强调when 引导的从句所表示的时间状语

强调句,强调状语,还原为it will lead to pref? only when the~~~