2.C

3. Plot, sound effects, scenes and actors

4.A

5.a and D: The most important thing is to render the atmosphere, but it can express the feelings of the characters and highlight the tension of the plot.

6.B

7. Is it limited to countries? ..... In fact, I think horror movies need the soundtrack most, like The Shining. Without that kind of noise-like soundtrack, the whole movie would have no feeling.

8. Sometimes a good soundtrack can make a movie magic, and the most important thing is to match the artistic conception of the movie content. Please continue to create!