For example, AIDS, the spread of per-contact probability of about 1%, with the increase in the number of contacts, the chance of infection is increasing.
2
早在上世纪80年代,就有人注意到了割礼和降低传染艾滋病几率之间的关系。
As early as the 1980s, it was noted that circumcision and a reduced risk of HIV transmission between.