December 10, 2010 The 30-day Challenge. Day21. 21. Your favourite subject to study. The English language. Seriously. It was my all time favourite subject in school! Share this:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on Pinterest (Opens in new window) Post navigation The 30-day Challenge. Day 20.The 30-day Challenge. Day 22.