"We will somehow travel across London."
Translation:Ni iel veturos trans Londonon.
I don't understand the word order requirement here. I translated the English sentence as "Ni veturos iel trans Londonon," which was marked wrong. Apparently "iel" must precede the verb if you use "veturos," but it can (or must?) follow the verb if you use "vojaĝos." Why?