Question: What actresses were involved in the scandal that temporarily separated the Hong Kong duo Twins in 2008?

Context paragraphs:
Twins Language: Twins Language is an album by Hong Kong duo Twins.  It is their third mandarin album.  It was released in January 2008.  It is their last album before break-up.

Edison Chen photo scandal: In 2008, intimate and private photographs of Hong Kong actor Edison Chen with various women, including actresses Gillian Chung, Bobo Chan, Rachel Ngan, and Cecilia Cheung, were unlawfully distributed over the Internet.  The scandal shook the Hong Kong entertainment industry and received high-profile media attention locally and around the world.  Many local newspapers headlined the story consecutively during the first fortnight of February 2008, relegating coverage of the 2008 Chinese winter storms to secondary prominence during Chinese New Year.

Twins (group): Twins are a Hong Kong Cantopop duo that was created in the summer of 2001 by Emperor Entertainment Group (EEG).  Twins are made up of two girls, Charlene Choi and Gillian Chung.  They are a popular group in Hong Kong and a top band in China.  Their fanbase have included Taiwan, Japan, Singapore, Thailand, Malaysia, Canada, Australia, United States, Vietnam and Philippines.  Their music was generally targeted at young teens, but in 2004 they began to attract a wider audience by venturing into different styles of music.  In February 2008 the duo temporarily separated after the Edison Chen photo scandal involving Gillian Chung.  After two years the group finally reunited in 2010.

Singing in the Twins Wonderland (Volume 4): Singing in the Twins Wonderland (Volume 4) is an album by the Hong Kong Cantopop duo Twins.  It is the fourth in their series of children's albums, and was released in August 2004.

The Twins Effect II: The Twins Effect II is a 2004 Hong Kong action fantasy film directed by Corey Yuen and Patrick Leung.  The film is a sequel to "The Twins Effect" (2003), but has a completely different story from the first film.  It starred Charlene Choi and Gillian Chung of Cantopop duo Twins in the leading roles.  Co-stars include Donnie Yen, Daniel Wu, Edison Chen, Wilson Chen, Tony Leung Ka-fai, Qu Ying, Fan Bingbing and Jim Chim.  Jackie Chan also makes a cameo appearance, along with his son Jaycee Chan who is in his debut.  The film's original English working title was Huadu Chronicles: Blade of Rose and its US DVD release title is Blade of Kings.

Twins Party: Twins Party is eleventh studio album by Hong Kong duo Twins.  It was released in September 28, 2007.  There are three versions released from the album: Standard Version, Gillian Version and Charlene Version.

Singing in the Twins Wonderland (Volume 3): Singing in the Twins Wonderland (Volume 3) is an album by Hong Kong girl duo Twins.  It is the third album in their series of their children's albums.  It was released in April 2004.  Whole four albums of "Singing in the Twins Wonderland" had a great success because they became very popular among children.  Twins had one more album released for children, named "Singing in the Twins Wonderland (Volume 4)".

Lonely Me: Lonely Me is debut studio album by Hong Kong cantopop singer Charlene Choi, member of the popular duo Twins.  The album is released in April 2009 in Canton-Hong Kong strike.  The album consists of two discs: Disc 1, CD, contains 12 songs and disc 2 is a DVD with 3 music videos.

Sport in Hong Kong: Sports in Hong Kong are a significant part of its culture.  Due to British influence going as far back as the late 19th century, Hong Kong had an earlier introduction to Western athletics compared to other Asia regions.  Horse racing has most spectators, while football, basketball, swimming, badminton, table tennis, cycling and running have the most participants.  Golf is an increasingly popular sport, despite the relatively few number of courses in the city.  In 2009, Hong Kong successfully organised the V East Asian Games and it was the biggest sporting event ever held in the territory.  Other major international sporting events including the Equestrian at the 2008 Summer Olympics, the Hong Kong Open Golf Championship, the Hong Kong Sevens, Hong Kong Marathon, AFC Asian Cup, EAFF East Asian Cup, Hong Kong Badminton Open, Hong Kong Tennis Classic, Premier League Asia Trophy, and Lunar New Year Cup.  Hong Kong athletes have improved in worldwide rankings.  As of 2010, there are 32 Hong Kong athletes from seven sports ranking in world's Top 20, 29 athletes in six sports in Asia top 10 ranking.  Moreover, Hong Kong is equally impressive performance of athletes with disabilities in 2009, having won four world championships and two Asian Champions.

Another Me (Charlene Choi EP): Another Me is the first EP by Hong Kong pop singer Charlene Choi, who is also a member of duo Twins.  The EP was released on October 15, 2009 under EEG, after her successfully album Lonely Me.  EP contains three singles: Survivor, Put Too Low and Happiness Air.

Supporting paragraphs: Twins (group) Edison Chen photo scandal
Answer: Gillian Chung, Bobo Chan, Rachel Ngan, and Cecilia Cheung