I hope this helps! These are just conversationally smoother... but you've got the right idea!

a: When did you start playing the game?

b: I just started playing now. 

A: Don't lie to me! The monitor is already hot! 

7)
a: Kelly, I just booked the movie now.>>>>> 캘리, 나 방금 영화 예약했어.
b: what movie are we going to see?
a: we'll see the horror movie.
b: I don't like the horror movies, should we change to another one?>>>>나 공포영화 싫어해. 우리 다른거로 바꾸면 안될까?

a:Kelly, I just bought tickets to the movie. 

b: What movie are we going to see? (You can also say, What are we seeing? or Which one?)

a: It's a horror movie. 

b: I don't like horror movies! Can we pick a different one? (or Can we pick a different movie?)

8)
a: Did you solve the question 4?
b: Ah,,,,,I can't remember what I wrote! what if I'm wrong?>>>> 아,,,, 뭐라고 썼는지 기억할 수 없어. 틀리면 어떻하지?
a: Almost everyone couldn't solve the question.>>>> 거의 대부분이 그 문제 못풀었어

a: did you get question 4?

b: Ah... I can't remember what I wrote. What if I'm wrong?

a: Almost everyone missed it. 

9)
a: are you possible to drink today?
b: Fine. don't worry about me
a: what if you get laid off? you already got late 3 times!!>>> 너 이미 3번 지각했잖아!

a: Did you drink (alcohol) today?

b:I'm fine. Don't worry about me. 

a: what if you get laid off? You were late 3 times already! 

(I think it is what you mean... I'm sorry if it's not!)

10)
a: what are you doing now?
b: I'm tuning my car.
a: what if the car breaks down?
b: It's right up my alley! Can you stop talking anymore?>>>> 이건 내 전문이라고! 더이상 말 걸지마.

I'm not sure what's going on in the situation. Is a wife bothering a husband and he wants her to stop talking to him?

If yes, we would just say, "Leave me alone." "Let me do my thing." "Stop talking (to me)." "Shut up."