Thanks a lot! Он не уркал meaning tried, but wasn't able, makes sense. In упражнение 1.6 my interpretation of Я не завидую всем means "I don't envy everybody". In 3.4 "Mum's the word" is something that I have never heard before, but emphasized in the lesson. I suppose it's kind of a cool idiom. Могила - as silent as a grave, is cool too.