Translation:The crayfish are alive when they die.
I'm probably a moron, but Annikajns's point seems good to me. Good for the course creators that they get the reference, but to most learners, riddles aren't helpful. I want to understand the words and grammar, and this question sows needless doubts about that which I have already learnt. I don't think the Rumpelstiltskin "riddle me this" stuff improves the course.
I generally agree, and I intend to remove most of these sentences from the course in the next tree version. Perhaps they'd be a good fit for the later parts of a later tree.
That said, I think the course was created with the assumption that there would be a proper hints system for sentence, that all users would be able to see forum comments, etc. Obviously, having sentences that require explanations doesn't work if there is no failsafe way of providing explanations.