NOT the students but their teacher ____ the film

填上is enjoying.
根据英语中的就近原则,空格前面的主语是单数,所以应该填is enjoying.
在："or ; either …or；nor; neither…nor；whether…or；not…but; not only…but also" 等词语连接的并列主语都需要使用就近原则.

is enjoying
就近原则