Conversation so far:
How did Wonder Girls' Hyuna's departure happen?
Hyuna was withdrawn from Wonder Girls by her parents due to their concern over her problems with chronic gastroenteritis and fainting spells.
What did the Wonder Girls do in 2008?
In February 2008, the Wonder Girls joined their producer Park Jin-young for his month-long concert tour through Korea and the United States as special guests.
What was the Wonder Girls' breakthrough?
Wonder Girls' single So Hot was released on May 22, 2008. The song topped online charts soon after.
What other interesting facts can you tell me about Wonder Girls' breakthrough besides the release of their single, So Hot?
In mid-2008, Wonder Girls performed on MBC's Show! Music Core, performing So Hot and This Time.
Are there any other interesting aspects about Wonder Girls' breakthrough besides performing on MBC's Show! Music Core?
Due to a vocal cord injury, Yubin temporarily lip-synced her parts under doctor's orders during the performance.
What other Wonder Girls' songs were released besides So Hot?
After a very short break, the Wonder Girls made a comeback in early fall 2008. The music video for Nobody was revealed, and the single was released simultaneously.
Where did the the Wonder Girls' film the music video for Nobody?

Question: Who was in the group at that time?
Self-contained rewrite: Who was in Wonder Girls during the time of their breakthrough?