a. In this era, most of the young people are impatient and this leads to crime.
My teacher corrected to
b. In this era, most young people are impatient and this leads to crime.
My question is, when to say “most of the young people” and when to say “most young people”?
What is the difference? When should I use most of the vs. most?
Using the definite article the only works if you're talking about a specific group of young people.
Most of the young students at this school learn English.
If you're talking about young people in general, then you need the null article.
Most young people are impatient.
With an singular noun, you need to use “most of the …”, e.g. “he ate most of the cake”. Grammatically, the situation looks different. But there is actually a reason behind this. In “most of the young students at this school”, most qualifies a specific domain (the young students at this school). In “most of the cake”, most qualifies a specific domain (this one cake). In “most young people”, most qualifies the non-specific group of all young people. Since there is no specific domain, there is no definite article.
There is no difference. "most young people" is the short form of "most of the young people". But when a shortened form has been found it is the preferred one. Google Ngrams shows this here
