1. You should obey the rules in the cinema.
   Correction: Remove "to" - "You should obey the rules in the cinema."
   (Correct as it is)

2. However, the rules here.
   Correction: This sentence is incomplete. It could be corrected to: "However, the rules here are strict."

3. Find and correct the mistake in each sentence.
   Correction: This is a directive. No correction needed.

4. She is hard-working.
   Correction: Correct as it is.

5. Therefore she isn't lucky in examinations.
   Correction: Correct as it is.

6. But the low salary.
   Correction: This sentence is incomplete. It could be corrected to: "But the low salary is a problem."

7. This is a/an ______ on real life during war in Vietnam in 1945.
   Answer: A. horror film

8. He ______ the Oscar Prize as the best actor.
   Answer: A. wins

9. She decided to quit this job ______ the salary.
   Answer: A. because of

10. ______ although
    Answer: C. However

So, to summarize the corrections and answers:

1. Correct as is.
2. "However, the rules here are strict."
3. Correct as is.
4. Correct as is.
5. Correct as is.
6. "But the low salary is a problem."
7. A. horror film
8. A. wins
9. A. because of
10. C. However