difference between "plural nouns with the" and "plural nouns without the"

Can I use "the" with plural form of nouns ?

(Say, "the horses", "the players" and etc..?

And when is it corect?)

• You would say "I like horses," if you like them in general but you would say "I like the horses," if you are referring the specific ones.

• you can use 'the' with plural nouns.
  
  "The green hats don't fit well"
  
  "The Porches are parked in the back"
  
  "Koz macks on alllllll the girls" 
  
  etc. 

• Usage of the definite article "the" in English is the same for plural nouns as it is for singular nouns.

• With plural, such as "look at the horses", "the strawberries are very sweet", etc. , you simply make the noun plural and use "the" if you are talking about them directly. For example:
  
  I have a horse.
  I like horses.
  What a beautiful horse.
  The horse is playing or the horses are playing.
  
  I know English can be very difficult to learn as there are so many rules. You speak well and these are little things that will come in time. I will try to find some sites that may help you. And please ignore Heycal as the only reason he is here is to poke his bony little finger in my side, and not to help.  

Omitting article “the” in front of plural nouns

(I'm helping someone learn English (second language), and I'm having trouble explaining when to use the and when not to. For example:

Students learn better when teachers are passionate about teaching.

versus

The students learn better when the teachers are passionate about teaching.

There's a subtle difference. The first one is a general statement, whereas the second might imply a study where a group of students learned better than another.

Is the difference simply that, general v. specific?)

• It seems I missed the 'question' in the title and answered only the last one.
  'The' isn't used with plurals when that plural implies a general reference, only when that plural implies a specific group.
  So...

  Students learn better when teachers are passionate about teaching.

  is the equivalent to: "Any student learns better when any teacher is passionate about teaching."
  Whereas...

  The students learn better when the teachers are passionate about teaching.

  implies that you're not talking about students in general but a particular group, for example those who study in a certain school or at a certain level; and the same goes for the teachers: you don't mean teachers in general.

• Yes, you are right that the difference between your two example sentences is simply one of generality vs. specificity. And this is a useful rule for a beginner to know when using plural nouns.
  Of course, it is not completely straightforward: the learner has to decide whether to use a singular or plural noun in the first place. Furthermore, it is not always obvious whether the group of things being referred to is the full set or a specific subset. And later the learner will find out that the definite article is used in front of adjectival nouns representing the full set (the rich, the unemployed, etc.) and often in front of nation groups (the British are always taking about the weather; (the) Germans are reputed to have no sense of humour).
  Nevertheless, while the choice of the correct article (or none) for singular nouns is complex, this rule about plural nouns is simple and worth learning.