Konnichiwa

I'm a little bit lost with the “oiwai de mo”. What is the construction of “oiwai de arimasu”. Why isn't it “oiwai ga arimasu” ? This refers to lesson 7.4

Arigoto

Olivier

こんにちは (Konnichiwa) Olivier,

Thanks for your question.

である (De aru) is what's known as the “literary form.” This is used a lot in formal writing or speeches. We can add it after nouns and な (na) adjectives. 

Essentially, it's just a very formal way of saying です (desu)! So お祝いであります (oiwai de arimasu) really just means お祝いです (oiwai desu), but sounds much more formal. 

By adding in the particle も (mo), we can say “also":
お祝いである (oiwai de aru) “it's a celebration” 

お祝いでもある (oiwai de mo aru) “it's also a celebration”

残念ですけど、お祝いでもありますよ！ (zannen desu kedo, oiwai de mo arimasu yo) "It's a shame but it's also a celebration, you know!

お祝いがあります (Oiwai ga arimasu) means “there is a celebration":

残念ですけど、お祝いがありますよ！ (Zannen desu kedo, oiwai ga arimasu yo!) It's a shame but there is a celebration, you know! 

This would be okay to use here if there were some sort of party or event happening to celebrate. However, in the case of this lesson, Sayaka and Kenny are simply talking about it being a cause for celebration, so it would sound a little odd to use お祝いがあります (oiwai ga arimasu) here.

I hope this helped! Please let me know if you have any other questions. 

勉強を頑張ってください！ (Benkyō o ganbatte kudasai!)

Thank you so much Emma san. It is very clear