Hi ENatanael. Not all expressions concerning amount are followed by only "de". There are some exceptions. See here under "on ne met pas d'article" and then = Mais après ces expressions de quantité, on met un article : http://www.bertrandboutin.ca/Folder_151_Grammaire/I_a_article.htm#_emplois_de_l'article_défini
- bien de = Notre fils nous donne bien du souci.
- la plupart de = La plupart des enfants aiment jouer
- la plus grande partie de = La plus grande partie des étudiants sont sérieux.
- la moitié de = La moitié des travailleurs étaient présents.
- la foule de
- la masse de
- la multitude de
- la totalité de
- l’assemblée de
- le cortège de
- la majorité de
I find it confusing also. I think in this case you use "de" instead of "des" as it's following a negation. This article gives a pretty good overview with examples:
Please let me clarify as I am not invalidating the word "spectacles." It is one of a number of words that could be used to translate "lunettes". However, a person who used that word in conversation with native (American) English speakers would signal their unfamiliarity with current usage. In consideration for the best word to choose, one should consider his/her audience. What English word do they use? Do your friends say "spectacles" or "specs"? Then go ahead. Those using this site to learn English will benefit from knowing that "spectacles", although correct, is not very widely used in the 21st Century American English, however common it is in classical literature. In short, would you like to learn modern, conversational French by committing to memory French words that went out of common use a century ago? Some people enjoy learning a wide variety of terms and get a kick out of alternatives that are rarely used, or are boning up for reading classical French literature. Some just like to see how far the envelope can be pushed. Whatever your personal goal, enjoy yourself.
Your comment that "spectacles" is not a widely used word, is quite incorrect. I assume that you are either an American or a Frenchman who was taught American English. There are many other forms of English spoken around the world ... including, Indian English/Australian/South African/Philippina ... I could go on. As there are over a billion souls residing in India alone, I can assure you that modern parlance in the States is not necessarily considered good English in the rest of the world. I currently live in the Middle East and am surrounded by people from all over the world and can assure you that LOTS of people use specs and/or spectacles on a daily basis. Perhaps it's time for Duolingo to look outward a little?
Kind sir: when I found my notion confirmed that "spectacles" was old fashioned on none other than the Cambridge (UK) online dictionary ( http://dictionary.cambridge.org/us/dictionary/british/spectacle_3 ), I made the error of assuming this term was little used. So with one click of the mouse I offended over one billion English-speaking people. I am sorry for that. I have always believed that learning another language was a way to help bridge the gap between cultures but did not fully realize how much I would learn about what I considered "my" language. I hope we can agree that regional differences throughout the world do not make one "correct" and another "incorrect" but merely different. Now let's all get back to learning French! Bonne journée !
The glasses that you wear are "lunettes", not "lunette". See here http://www.larousse.com/en/dictionaries/french-english/lunette/47994 and here http://www.oxforddictionaries.com/translate/french-english/lunette