"Tourists like to climb Mount Kilimanjaro"
Translation:Watalii wanapenda kupanda mlima Kilimanjaro
The sentence to me seems to be asking for the hu- tense, but no, Duo wants the present continuous tense and marks the hu- tense wrong. One starts to get the idea that the hu- tense is only wanted when you are working on the habitual (hu-) tense module. Anyway, I reported that my answer "Watalii hupenda kupanda mlima Kilimanjaro" should be accepted.