Hundreds of thousands of people took to the streets to mark the occasion.

数十万人走上了街头纪念这一时刻。

They issued a special set of stamps to mark the occasion.

他们特别发行了一套纪念邮票。

To mark the occasion, two exhibitions have been staged in Moscow.

为了纪念这一特殊时刻，莫斯科举办了两场展览。

Today, people eat glutinous rice cakes to mark the occasion.

今天，人们通过吃粽子来庆祝端午节。

They might also be a social gathering or ball to mark the occasion.

他们也可能以社交聚会或举行舞会来纪念这个日子。