CLEAN : Football: Ronaldo appears in court over tax evasion claims

The video tutorial discusses national customs and addresses the uncertainty or lack of knowledge about them.

What does the phrase 'Back on the national custom' imply?

How can cultural customs influence a person's knowledge?

Discuss the implications of being unaware of national customs.

What might be the significance of someone not knowing something?

In what contexts might someone say 'He doesn't know'?