"She runs in a field."
Translation:Ella corre en un campo.
Have those words been presented in the Duo vocabulary? I don't expect Dou to accept every definition that there is for 'field,' just the ones they have used.
Probably not, rsp, but not having them be ancillary, if unpresented vocabulary that would be accepted in the test at the end of the module sort of frustrates someone who opts for testing out of a given skill. It's like having a module on, say, eating and things on a dining room table, and responding with "bandeja" for tray, when the module only presented "charola," o viceversa. There's wrong, and then there's wrong according to the parameters of the test.