Audio File

Hi,

What I want is for the students to complete the audio file in base layer and then continue to click on slide layers. I created a true/false variable that an incomplete message would show up if the students didn't complete listening the audio file in base layer. However, the trigger only works once. When I revisited this slide, the incomplete message didn't appear if I clicked on slide layer without finishing the audio file in the base layer. 

I attached a story file here. Please let me know if I set up anything in a wrong way. Or, if anyone has a better idea to prevent the students from clicking on slide layer before they finish listening the audio file in base layer. 

Thanks,

Yun