'There's' is a contraction of the words 'there is.' When using the word 'nothing' you are suggesting that something cannot happen or be done.
'There's'是'there is'的缩写形式，当用'nothing'这个词的时候，你是指某事不能发生或被做。
Here are some examples: 这里有一些例子：

"There's nothing you can harm." 

你没什么可以伤害的。

"There's nothing the police can identify." 

警察没什么可以辨认的。

"There's nothing we can agree on." 

我们没什么可以同意的。

"There's nothing we can join." 

我们没什么可以加入的。

"There's nothing she can cook." 

她什么菜也不会做。

"There's nothing my dog can learn." 

我的狗什么也学不到。

By using the word 'cannot' or 'can't' you change the expression to mean that all is possible.
通过使用'cannot'或者'can't'你就改变了表达方式，意味着一切皆有可能。
Here are some examples: 这里有一些例子：

"There is nothing I cannot ask for." 

没什么是我不能要求的。

"There's nothing we cannot accomplish." 

没什么我们不能完成的。

"There's nothing our dog cannot open." 

没什么东西是我们的狗打不开的。

"There's nothing that truck cannot move." 

没什么是卡车搬不动的。