Certain elements of the course too easy?
I just started using duolingo again after a long absence and the next thing on my to do list was prepositions. One thing I noticed is that a learner could just race through this section without actually learning what the prepositions mean/ how to differentiate between different prepositions in the course because they know generally what a prepositional pronoun looks like.
The question would be "How do you say 'to me'?"
The example answers would consist of one preposition and two random unrelated words. I was just finding the two random words and then clicking the odd one out without actually thinking about it.
Surely (to make it somewhat challenging) the three answers should all be prepositions, possibly all from the same category. Or at least a minimum of two prepositions as potential answers to test whether you really understand how to differentiate between them
One preposition and two random words; http://i.imgur.com/Fj5Y9BY.png
All answers using the same preposition, so not really testing your knowledge of prepositions but practising verbs/sentence structure. http://i.imgur.com/9p4VMvn.png
In the examples you have shown, I agree that they should be a bit more focused and maybe a bit more challenging (though not too challenging ;) We don't want to learners to give up) but unfortunately, the types of exercise you have shown are automatically generated by Duolingo. In the first example, the system just chooses random words from the course. Since we can't fix this ourselves, I might at least bring it up with the Duolingo team that those words should all be taken from the same skill or some other alternative. In the second example, the sentences (except for the correct answer) are randomly generated (though it seems the system does try to use similar words where possible). The randomisation is very hit-or-miss. Again, I'll bring the topic up with the Duolingo team and see what can be done. Also note that this is not unique to the Irish course :)
TL;DR: These types of exercise could probably do with some revamping, but it isn't up to us contributors to fix them. The Duolingo team is the best group of people to bring this up with :) It's unclear what kind of changes could be made...some people would prefer these exercises to be harder, but you would also have to consider how effective they are at teaching the language in the first place.