Practice Russian the friendly way — with free, interactive exercises. Work through grammar, vocabulary, and reading by topic and level, and check your answers as you go.
Two decisions in every sentence: which of the three prepositions belongs in the gap, and what form the word in brackets takes after it. No verbs of motion here — nothing is going anywhere. Your clue is what the sentence is actually about: a place, a channel, or a subject.
Two decisions in every sentence: which ending the word needs, and whether с belongs in front of it. English gives you with for both, so this is the one place Russian asks you to think about something your own language never made you notice.
Where is it, and where did it happen? Every sentence needs в or на plus the prepositional form of the word in brackets — and the words are not all singular, so keep an eye on the endings.