I am stuck on Past 2 strengthen. I am on 4/5 and cannot get up to full. I have done the exercise several times with all answers correct and it will not move. I have also tried 'beat the clock' several times. I have not had such problems with other languages. It also seems that the themes renew too quickly so I am not able to progress.
There seem to be some skills where the strengthening exercises don't include all the words, so they never strengthen to 5/5. I seem to recall Verbs Present 1 is one of those, maybe Past 2 is similar. I guess it's one of the joys of Beta! The way round it is after doing the strengthen is to re-do the individual lessons until it reaches 5/5 ... you should then know which lesson contains the missing word, and next time shouldn't need to re-do all the lessons, just strengthen and then that one.