Thanks for making this tool, highly useful!
In the example you used, more native way is to include the "把" verb structure i.e. 你得把鞋带系好 instead of 你得系好鞋带.
I was thinking if this could be improved by adding some examples in the prompt? I've heard that LLMs are good with learning by examples. I'm not sure if it works since you're first getting the English output and then translating it.