Here’s a potential completion for the passage based on the context provided:

It is said that we no longer remember the original meaning of festivals, and that most of us treat them as opportunities to have fun. (1) **A**. Because it is generally agreed that enjoyment seems to be the priority during festival times, it doesn’t seem to be the case that people have forgotten (2) **B**. what these festivals mean. For example, religious and traditional festivals have certainly become times for celebration. In the UK, Christmas is a good example of a festival period (3) **A**. when people are most concerned with shopping, giving and (4) **A**. receiving presents, decorating their homes and enjoying traditional meals with their families. Most people look forward (5) **C**. to Christmas as a holiday period, rather than a time to practise religion. Similar behaviour (6) **A**. can be seen during non-religious festivals, such as Bonfire Night. People associate this occasion with making fires, watching firework (7) **C**. displays, and perhaps going to large events in local parks; in other words, enjoyment is people’s primary goal. In Vietnam, Tet (lunar new year) is considered the biggest festival (8) **B**. because it is the time for people to enjoy festive atmosphere and (9) **A**. perform dances to commemorate ancestors and worship gods. In conclusion, although people mainly want to enjoy themselves during festivals, it is agreed that they are (10) **B**. unaware of the reasons for these celebrations.

This fulfills the passage, maintaining logical continuity and proper grammatical structure.