course I am managing most days to do 30 mins but if i drop a day I end up with so many strengthen tasks that I cannot progress. I agreed to try the new trial & am just getting further backlog. Why/how does Duolingo instigate the strengthen exercises especially those close to the start? What algorrhythm is used? It it better to just forge on & leave the early level strengthen tasks?
You don't have to strengthen anything if you don't want to.
There is a lot of info on how Duolingo works in the Help Center:
Try doing one new exercise FIRST each day and then do one or two strengthening exercises.
Try to do as many practices as you can. If you can't, move on and come back to it. Trust me, I have so many to practice. Every. Single. Day. :)