ANDREW:

There are 5 national holidays in my country.

CORRECT!

ANDREW:

My favorite holiday is Hangeul day.
Because my birthday is after one day Hangeul Day.

CORRECT:

My favorite holiday is Hangeul day because my birthday is the day after it.

>"Because" heads up subordinate clauses, which means if you have a clause that starts with "because," you must also have a main clause in your sentence. A main clause is something that could be a complete sentence by itself. The main clause can come first or last; if it comes last, you need a comma.

ANDREW:

Q:What do you usually eat on that day?
A:There is not special food.

CORRECT:

A: There is no particular/special food that we eat on that day.

> Complete your sentence.

ANDREW:

Q: WHat do you usually do on that day?

A: People draw period of King Sejong.

> What do you mean by "Period of King Sejong"?

Q:What do you like about this holiday?

CORRECT:

A: I recommend you to celebrate Hangeul Day.

> Your answer didn't match the question, but you can rephrase it like this:

A:  I recommend you to try celebrating Hangeul Day for you to find out why I like this holiday.