Your question is quite old, so I guess you have already figured it out. Still there's no answer, so just in case someone is interested: "tirare" means both "pull" and "throw". Only context can help discerning. To avoid ambiguities, you can use synonyms, like "lanciare" (a bit -- just a bit -- more formal) and "gettare" (which can be used when you are not really aiming at anything in particular)
Anybody else thinking of this? http://www.cbs.com/shows/i_love_lucy/video/1998955157/i-love-lucy-i-speak-italian
When I first encountered " tirare" the hover showed " pull out " as an acceptable translation. I therefore translated this as " The man pulls out the knife" and lost a heart. On hovering over "tira" in this sentence it is translated as throws. It seem to be advisable to hover over every highlighted word as the meaning can change from sentence to sentence.
I would love if duolingo was completely consistent too and I do get frustrated when I lose a heart too. Then I try to remember that. failing is not the important thing the primary objective is learning and I used the annoyances to help me to learn. Luckily I smelled a rat when my first instinct was to translate to 'The man pulls the knife' but it seemed a little too gory or violent so I peeked... Not that throwing the knife is entirely without violent connotations. Anyway, to help me learn, the next time I see a door in Italy that I should PULL to open, I'll be temped to THROW it open instead. There's nothing like a bit of theatre to get attention!!.
He could have thrown an axe, so I am relieved. Unless this sentence is used for humorous effect (and consequently, it calls for so many witty responses from the students), I don't really understand why this choice of a sentence. If they want us to remember the word "knife", they should have used it frequently enough in previous lessons. In this case, we are in process of learning verbs, aren't we? So, instead of having us focus on the verb, they shift our attention to the noun and, in turn, to the situation. I don't think it is serious enough and makes the system rather chaotic. It still has its benefits, however, with all its visible flaws.
"The man pulls the knife", would/should work, so should, "the man throws the knife". How does one discern context?