It's based on the airing schedule https://kisskh.at/photos/j1rQb_3 Many cdramas have their own schedule…
You're very welcome~ Cdramas usually post a release schedule (such as on Weibo social media account) and most of time MDL users will upload it to photos so it's easier to access
can someone tell me why some days we have 1 ep and some 2? which days do we have 2 ep?
It's based on the airing schedule https://kisskh.at/photos/j1rQb_3 Many cdramas have their own schedule and you can usually find it in the photos section on MDL
Came across AvenueX's interview with the director of My Mr. Mermaid and it was interesting to learn about the production and the amount of effort that went into making the drama. https://youtu.be/U93yVRtvt0g
K-Drama 
3 
4 
1 
Cdramas usually post a release schedule (such as on Weibo social media account) and most of time MDL users will upload it to photos so it's easier to access
Many cdramas have their own schedule and you can usually find it in the photos section on MDL
Just wait for the 15-30 sec ads to play first and you can select the other ep trailers on that site