Помогите составить вопросы к предложению. This little machine gave him a key to the invantion of the telephone. Пожалуйста!!

Did this little machine give him a key to the invention of the telephone? This little machine gave him a key to the invention of the telephone, didn't it? What gave him a key to the invention of the telephone? What did this little machine give him a key to? Did this little machine give him a key to the invention of the telephone or the radio?