orange as adjective in plural sense
i was totally stumped on this one: Elles peuvent être rouges, orange, blanches, jaunes et bleues. first, i could not differentiate between elle and elles so did not pluralize any of the colours. That aside, why is orange not pluralized with an "s". Is this an exception?
Yes, "orange" is an exception in that it doesn't have to agree in number or gender with the thing it describes. (However, sometimes you see the slightly different "orangé" which will take an extra e and/or s as the case may be). Anther exception to the rule is "marron" (brown). The reason is that these color names are actually names of fruit, therefore nouns, and nouns cannot just switch genders and numbers (marron = chestnut, and orange = well, orange!) The same goes for any sort of modified color like "jaune clair" (light yellow), "bleu foncé" (dark blue) or "blanc cassé" (off-white) etc.
ricainrico is exactly right about this. And as for differentiating between "elles" and "elle", the clue was the "v" sound in "peuvent" as opposed to "peut". This is what French native speakers use to make the difference because you are quite right; no difference can be heard between "elle" and "elles" in this particular sentence.
Hope this is helpful.
I reported it before I saw this thread, but looks like Ricainrico is right http://french.about.com/library/begin/bl_colors.htm Google comes up with a Canadian site where 'oranges' is used though http://www.quebecscience.qc.ca/Investigatron/Environnement/Les-vers-de-terre-peuvent-ils-etre-oranges-ou-bleus-