There are about 150 prepositions in English.
Prepositions are challenging for learners of English because 1:1 translation is usually not possible. One preposition in your native language might have several translations depending on the situation, and vice versa.
Prepositions and nouns make up PREPOSITIONAL PHRASES that give details on time, space, and direction. PREPOSITIONAL PHRASES can function as a noun, an adjective, or an adverb.
My mom is sitting at the desk.
My mom laughed at my joke.
My mom goes to bed at 9pm.
She goes to work at 7 am.
My friend told me all about it.
Mrs. Esteban lives near our house.
After recess we’ll be in our classroom.