iphone: genders when building sentences
In the "build a sentence by dragging together different words" type exercises on the iphone version, there are sometimes complete random words in the choice of words to use (good), but usually, there aren't any 'deliberate' false choices, i.e. ensure that if 'la' is an option, then 'el' should also be there (las/los; nosotros/nosotras; ...). That would give the extra opportunity to also check my own knowledge of what gender a word has.
(particularly, sometimes - if I am unsure about what the right word is, more often than not, only seeing a masculine or a feminine article already kind of gives away what type of word I need to be looking for.