Hello the Woojung,

Thank you for submitting your homework and sharing about your weekend activities.

Please take notes of my corrections. ^_^

Wojung: On the weekend I usally go to my grand parents house with my family.

Correct: On the weekend, I usually go to my grand parents' house with my family.

**EXPLANATION**
~ Don't forget to use the proper punctuation mark.
~To show possession, don't forget to use apostrophe (') after the name of the owner.

Wojung: Thins weekend I don't have a plan yet but I am sure I will spend good time.

Correct: This weekend, I don't have a plan yet but I am sure I will have a good time.

**EXPLANATION**
~Always check the spelling.~ You are pertaining to "having a good time" not to spend it good.

Wojung: I think weekend is great time for people because they can rest after hard work.

Correct: I think weekend is a great time for people because they can rest after hard work.

**EXPLANATION**
~ Don't forget to use articles.