Translating english into spanish
Most of the problems have me translating a Spanish sentence into English. I would like to be given a question written in English and then translate it into Spanish.
That's because Duolingo doesn't want people who just started learning Spanish to post their makeshift Spanish sentences on the web. (No offense intended :) ) If you think your Spanish is advanced enough, you could try to 'learn English' and pretend you are a native Spaniard. ;) Then you will get an English sentence from the web which you can then translate to Spanish. :)
You can click on the language you're learning (top right of duolingo page) and that will take you to your basic info page where you can change the language you're learning. Change it to English (yo se Espanol) and you get lessons in English which can be useful because you have to translate into Spanish, and you also get documents in English to translate to Spanish. It's a little harder, because you don't really know if your translation is good, but I guess I'm going to find out! :-)
I think that's an excellent suggestion. DuoLingo can evaluate your English translation of a Spanish sentence so the reverse process should be do-able. I've noticed that the further you get into the lessons, there seems to be more English sentence to Spanish sentence translation requests. Only the DuoLingo staff can explain their thinking on this topic.