New year, new classes, same old problem

So the summer holidays are a dim and distant memory, the new school year has started and I've got to know several new classes. Today I collected their first written homework. It appears that this bunch are no better at using the dictionary than last year's..... The very first paper I picked up has the following superb example of both how not to use the dictionary and the need to be able to spell in one's own language:
"She burned herself while she leathered her chips."

to cook: cuire
leather: cuir