There is something to be aware of when using the mint on your face.
请问，这个句子应该是There is something to be aware of when you are using the mint on your face的简写吧？也就是状语从句省略主语和be动词的问题。
这里从句和主句主语不同，但从句还是将主语和be动词省略掉了，是基于什么语言现象省略掉的呢？是由于省略掉you are并不会引起歧义吗？
There is something to be aware of when using the mint on your face.
on your face 这个词组，已经暗示 using 的逻辑主语是 you。不需要考虑主句，特别主句是There be 存在句，除此之外，to be aware of 的逻辑主语也已经暗示出来了，是 you。以下三句都可以：
There is something to be aware of when you are using the mint on your face.
There is something to be aware of when using the mint on your face.
There is something to be aware of using the mint on your face.
又如这句， Having trained 的逻辑主语是哪个的问题：
Having trained for five years before making her debut, there is no denying the black pink stars hard work ethic and dedication to her craft.
【翻译】在初次亮相之前，她已经同意了五年的练习，不能否认，这位黑粉明星勤奋的职业道德和对艺术的奉献精神。
我觉得，介词短语 before making her debut，意思等于从句 before she made her debut，已经提供了 having trained 的逻辑主语是 she。即使这个介词短语本身，里面有 her，也足以暗示逻辑主语是 she。
