A few days ago, I read a Washington Post report on the AIDS population in China. The author said Chinese people's sexual activities are at the mercy of god, because the central government fails in providing preventive protection and medical support to those who are exposed to the sexually transmitted deseases. It is said that at least 14 million people in China are involved in sex industry. Considering such a huge base, the spread of HIV may go beyond our imagination. The cruelty will be: Some innocent people will be HIV-infected. For instance, a wife may be HIV-effected because her husband has ever visited prostitutes. In some sense, it is true that Chinese people's sexual hygiene and safety are at the mercy of god.

If a person's fate is completely uncertain, we may say he is at the mercy of .... For instance, if you are on a sinking boat in the torrential hurricane and no rescue is available, you are at the mercy of nature.