strengthened 3 skills at once
The challenge to keep the tree golden can be daunting at times. The more pleasantly surprised I was this morning when "strengthening" resulted in 3 skills strengthened at once! I haven't had this before. (2 sometimes.)
Were you strengthening a particular skill or just doing a 'general' strengthening?
When I have a whole tree that needs strengthening (I come and go from Duolingo), I will sometimes purposely pick to strengthen the more advanced skills, because it will carry the earlier ones along with it, where it built on previous vocabulary etc.