问：I am go glad to contact you. I am in UK. I donot have a Chinese software, so I have to write this one in English. I am so sorry for that. I would like to ask you some questions about AIDs. Is mouth to mouth kiss dangerous or not if your partner is HIV positive? One of my friend, who is gay, also want to know how dangerous to have an oral sex with a man who is HIV positive since the gay usually donot wear condom for oral sex? How can a gay protect himself from HIV if you donot wear a condom for an oral sex? AIDS seems have a long period development before it become dangerous disease. Is any chance that a person, who is HIV carrier, can be tested HIV negative because this long term period potential. Can he transfer hispotential HIV virus to the people even he is tested negative for HIV? Can I say is it 100% safe if I have a sex with a person, who just test HIV negative? Thank you very much and I would be very appreciate to you if you can help me to answer above quesiton, which are real important to me and my friend.