As long as it's plural, add "the" before it

As long as it's plural, add "the" before it

No, you've misunderstood it. The definite article is used like this: it means the person or thing mentioned above
He bought an English Chinese dictionary this morning.The dictionary is very good.
② Used before a singular countable noun to indicate a whole or category
The panda is a rare animal
A panda is a rare animal
③ Used to represent something unique in the world
For example: the sun, the moon, the sky, the earth, the world
④ A noun used to indicate class or party
Such as: the Chinese Communist Party, the working class, the proletariat
⑤ It is often used before proper nouns containing common nouns or adjectives
A. Used before many nouns such as rivers, seas, mountains, archipelago, etc
The Yellow River The East Sea the Himalayas the Pacific Ocean
B. Used in the name of a country consisting of common nouns:
The People’s Republic of China the United States
C. It is used in front of such nouns as organs, organizations, dynasties, times, newspapers and magazines
the United Nations the State Council the Tang dynasty the People’s Daily
the Summer Palace the Peace Hotel the British Museum
⑥ A noun used to indicate position
For example: the east the southwest the middle the Far East on the left
⑦ It is used in front of musical instrument nouns, but it is not used in front of musical instruments in Chinese pinyin
Play the piano play the violin play Erhu
⑧ Before a plural surname, it means two couples or family. In this case, it is plural
When we got there, the Lius were waiting for us
The Smiths watch TV every day.
⑨ Used before some adjectives or past participles to indicate a class of people or things
The poor the rich the living the young
the wounded the oppressed the beautiful
⑩ Used before the superlative or ordinal of an adjective
After the game, the first thing they wanted to do was to take a hot bath

Can the plural of a noun be preceded by the?

There are three ways to express species (take elephant for example)
1.An elephant
2.Elephants
3.The elephant
4. The elephants

Do you need to use the plural when there is the "the" in front of a noun

Whether there is the in front of a noun and whether he uses the plural or not are two things that have nothing to do with it
For example:
The boys
The boy
Good luck!