Singing the Eugene Onegin choruses is a particular delight amongst the various opera choruses I’ve now sung. They also present a few challenges that are worth comment.
The dominant challenge is that the length of phrases is unusual. The opening chorus contains some long lines where the ideal spot to breathe happens later than you might expect. Here’s one such example, with my preferred breath spot marked:
With the “Adagio” tempo marking, you need to prepare in advance to reach the ideal breathing spot. You also have to construct the phrase musically in a way that makes sense with the language and the larger musical context. My ideal stress point are the downbeats of bars 11 and 12.
As with a lot of this music, those stress points don’t have to happen on the highest note in the phrase, so you need to restrain yourself and not just blast out the higher tones. It’s a challenge, but when it all comes together, the effort proves itself worthwhile.