Team China Olympic Line-up

Dear Alois and Jeff,

I am very much confused for China's line-up in the London Olympics. Wang Hao and Zhang Jike are qualified already for the singles events, but as for Ma Long, who still qualified in the Asian Olympic Qualification, why isn't he participating in singles? Why only on team events? If so as Liu Guoliang has said, how come Koki Niwa who has won the first round of the Asian Olympic Qualification is also for team events only? Is it true that only 2 players are allowed for singles per country? How come this wasn't the same when China snagged all the olympic medals in 2008 (Ma Lin, Wang Hao, Wang Liqin)? If Ma Long is only going to participate by team event, and suppose he teams up with, for example, Wang Hao, will Zhang Jike still participate in doubles or will China still find Xu Xin as the fourth member to line-up with Zhang? I am so confused. Please help.