"Lehrer haben Wasser."
Same as in English... "Teacher has water" sounds odd (we'd say "The teacher has water"), but "Teachers have water" sounds ok, although we could say "The teachers have water", which would be a slight change to the meaning of the sentence.
Does anybody know if this same change to the meaning happens in German between "Lehrer haben Wasser" and "Die Lehrer haben Wasser"?
"Teachers" is "Lehrer", while "the teachers" is "die Lehrer". If the original sentence omits the article, you should omit the article in your translation as well.
I'm guessing that putting the article would change the meaning as it does in English -- "Teachers have water" is stating something about teachers in general, while "The teachers have water" is speaking about a particular set of teachers.
The thing I would like to see is an area where the conjugations are laid out in tables for the verbs. Also, does anyone know if there are rules in German that will help you learn what nouns are plural, masculine and feminine? its kind of hard to tell when things are just thrown at you. right now I'm having to memorize articles and words together.
Whenever a verb is in a sentence you have to translate, you can hover your mouse cursor over the verb, then when the meanings box appears there will be a "conjugate" button on it, which you can click to see a conjugation table.
There are some general rules, like for instance words ending with -heit, -keit, -schaft, -ung, -tät are Feminin and words ending with -chen, -nis, -um are Neutrum. I think this is not a comprehensive list of these rules, but it's of some help already.