Bonjour ..
articles déterminants = le, le les
le --> masc. sing.
le --> fem. sing.
les --> masc. & fem. pluriel
Livre : masc. noun = le livre; <u>les</u><u> livre</u><u>s</u>
Stylo : masc. noun = le stylo ; <u>les</u><u> stylo</u><u>s</u>
Crayon = masc. noun = le crayon ;<u> </u><u>les </u><u>crayon</u><u>s</u>
montre = fem. noun =<u> la montre </u>= les montres
sac à dos = masc. noun =<u> le sac</u> = les sacs
So you have to look carefully to the endings fo the nouns, if they are plural or not...<em> You use the</em><u> "L' "</u><em> only when the following noun begins with a vowel OR a mute 'H' ....</em>
<em>l'</em><em>h</em><em>ôpital, l'</em><em>h</em><em>omme, l'</em><em>o</em><em>rdinateur, l'</em><em>î</em><em>le............... 2 have got a mute 'H', 1 is masculine, 1 is feminine .......</em>
<em>So back to your sentences and so sorrry for my poor English !!!</em>
Les livres, les stylos, les crayons et la montre dans le sac à dos de Marie sont tous neufs.
You would have written "<u>les</u> montre<u>s</u>" & " l<u>es</u> sac<u>s</u>" if the 's' for plural was behind the nouns 'montre' and 'sac'.......
