1 of an important event
ADJ. first, second, etc.
VERB + ANNIVERSARY celebrate, commemorate, mark They held celebrations to mark the anniversary of Mozart's death.
ANNIVERSARY + VERB be, fall The anniversary of the founding of the charity falls on 12th November.
PREP. on an/the ~ on the 20th anniversary of his death
2 of a wedding
ADJ. first, second, etc. | wedding
VERB + ANNIVERSARY celebrate
PREP. on sb's ~ He bought her a diamond ring on their tenth wedding anniversary.
PHRASES a diamond, golden, silver, etc. wedding anniversary