Translation:I always wear a watch to know the time.
mjustiniano1's response is actually incorrect, it's not uncommon to idiomatically refer to the time as "the hour" in many English speaking communities. For example, you could ask what hour it is, speak of the hour being near, or discuss the hour at which something might happen; ie, "knowing the hour."
In some cases it can: "Io parlo" can be translated as either "I speak" or "I will speak" or "I am speaking". I could take it a step further and say "Sto parlando" to really emphasize the fact that I am currently speaking. However, with this sentence, you wouldn't use the gerund form in English because "I always wear a watch to knowing the time" doesn't make sense in English. The gerund form, in English, is only used after some (but not all) other verbs, after prepositions, or as the subject of a sentence. Check here for specifics.
As Lena says, orologio comes from the Latin hōrologium, which derives from the Greek hōrológion, meaning hour count.
In English, horology is the study of time (from hora = hour, season; logy = the study of).
Once again, it's absurd to not take "I bring". "Bring" is listed as a correct translation for "Porto" on hover. I have reported this mistake and it's so frustrating to wait for the Duolingo staff to update their list of correct translations. The Italian course has been out for months and these quality issues persist.
Thanks for the suggestion! The course gets better thanks to perceptive users like you. You're right, there are a few words in this sentence that have more than one meaning: portare (bring, carry, wear) and orologio (watch, clock) so now you can even correctly say "I always bring a clock in order to know the time." ;)