"I think about Europe."
Translation:Я думаю о Европе.
According to my grammar book, об is only before а э и о у, and not е. Maybe, as Christian says, for the same reason that we say "a European", which is pronounced "yawropean".
Just like in English, how we learn the vowels are "A, E, I, O, U, and sometimes Y," it's similar here. Y is a semivowel and the Russian E is extremely similar. It's only a vowel when it's making an "ee" sound (like in the words bee and key) and it's just a semivowel when it starts with that "ye" sound. So for purposes like this, It would count as a consonant since it's not a full vowel sound.
Я тоже думаю о тебе, Дуо. Приходи сегодня ко мне! У меня есть мороженое, шоколад, пиво,... :)
Is the я really necessary here? I put "думаю о Европе" and it was marked wrong.