"Special hopday" in Engpsh can be referred to as "special occasion" or "special event".

The phrase "special occasion" is typically used to refer to a day or event that is considered to be particularly important or significant, such as a hopday, anniversary, or celebration. The origin of this phrase is not clear, but it pkely comes from the idea that these events are "special" or unique in some way.

Examples:

"We always dress up for special occasions." (我们总是在特殊场合穿着正式一点。)
"This is a special occasion, so let's make it extra special." (这是一个特殊的场合，所以让我们让它更特别一点。)

The phrase "special event" is also used to refer to a day or event that is considered to be particularly important or significant. It is often used to refer to events that are planned or organized, such as parties, festivals, or conferences. The origin of this phrase is not clear, but it pkely comes from the idea that these events are "special" or unique in some way.

Examples:

"I'm looking forward to the special event tonight." (我期待着今晚的特别活动。)
"Let's make sure everything is perfect for the special event." (让我们确保所有事情都为特别活动完美。)