A. What are good and bad study habits?

 -  I always check my study plans before studying. ✔​

It is my good habit of studying and bad habit is that I think the other things when I study so I can't concentrate on the contents of a book.

  => My good habit is studying, while my bad habit is thinking of other things while studying. As a result, I can't concentrate on the book I am reading.​

  => Corrected : The sentences are corrected grammatically.   

B. Make these sentences into English.

-난 네가 무슨 말을 하고 있는지 모르겠어. (I can't understand what are you saying.)

​=> I have no idea what you're talking about.​​

=> Your answer is correct but here's another way of saying it. 

-커피 남은 것 있니? (Do you have any left coffee?)

​=> Is there any coffee left?​​

=> Your answer is correct but here's another way of saying it. 

-나는 방학 때 여행하고 싶다. (I want to go trip on a vacation.)​ 

​=> I'll like to hit the road when I'm on vacation.​​

  => Corrected : The sentences are corrected grammatically.  ​