Translation:My cellphone's battery is empty! I don't know what to do!
Firstly, those are american idioms, not English language itself. Secondly, this is the Hebrew course, and so you should aware yourself that idiomatic expressions like "out of juice" won't sound the same as they do in other languages. ריק means empty. And so it should be translated. It doesn't matter how it's more commonly said in an average american daily conversation.