也会使得你更开心，因为情绪是相互传染的。
Which tends to make you even happier, since emotions are contagious.
其中一部分来自常见的北美流感病毒，自1999年以来，它由本地猪通过呼吸相互传染。
Some of it is from viruses that are common in North America, native to pigs that have coughed it onto each other since 1999.
虽然HIV病毒在家庭成员之间的相互传染是可能的，但它发生的几率很低，有记录的病例非常罕见。
Whilst HIV transmission between family members and members of the same household is possible, it occurs in extremely low numbers and documented cases are very rare.
应用推荐