That's weird. In the previous sentence that used the word lograr (I believe it went "Lo podemos lograr!"), I typed: "We can do it!" and got it right. This time, when I typed "We have to do it." I was marked wrong. Ugh ...
A few sentences ago "We can do it!" was accepted as a translation for "¡Lo podemos lograr!" ...so...why not "We have to do it." as a translation for "Lo tenemos que lograr."...? I'm confused. Does "lograr" have a different meaning with "have to" than it does with "can"? (Edited to add - I tried to report this as a problem, but the "submit" button won't work for me. It seems to be disabled. Does anyone know if there's another way I can suggest this as a translation problem? Thanks!)
"We must do it." was marked wrong on Feb 20th 2016. Even though for most situations my translation would probably be appropriate I suppose there is a subtle difference between "We must do it." and "We must achieve it." The first is more of a general action and the second more of something given, accomplished or acquired. Still in English "We must achieve it." sounds a bit odd.
They are not the same in Spanish: http://www.spanishdict.com/answers/130851/is-there-a-difference-in-meaning-between-tener-que-and-deber