1 “Virii” is used occasionally but discouraged. “Viræ” is definitely wrong.
1． “virii”偶尔会被用作virus的复数，但通常不建议这么使用。至于“viræ”这种用法绝对是错的。
2 Any upper respiratory infection can actually be the cause of the “common cold.”
2． 任何上呼吸道感染都可能是“感冒”的起因。
3 The immune response is actually the cause of your symptoms, not the virus itself.
3． 造成感冒症状的是自身免疫系统的免疫应答，而不是病毒本身。
4 Mathematically, this must be true. If the average were less than one, the virus would die out. If it were more than one, eventually everyone would have a cold all the time.
4． 数学上来说一定是这样的，因为如果平均感染数小于1，那么病毒最终就会灭绝；如果平均感染数大于1，那么总有一天所有人都会被感染。
5 (450 million people).
5． 4.5亿人。
6 (650 million people).
6． 6.5亿人。
7 I first tried to take the question to Boing Boing's Cory Doctorow, but he patiently explained to me that he's not actually a doctor.
7． 我起先找的是Boing Boing博客的科里•多克托罗（Cory Doctorow），但他很耐心地向我解释说他实际上并不是真的“多克托”（doctor）。
8 The residents of St. Kilda correctly identified the boats as the trigger for the outbreaks. The medical experts of the time, however, dismissed these claims, instead blaming the outbreaks on the way the islanders stood around outdoors in the cold when a boat arrived, and on their celebrating the new arrivals by drinking too much.
8． 圣基尔达岛上的居民们坚持把外来的船只认定为疾病爆发的诱因。然而那时的医学专家却不赞同这一观点，他们认为岛民在船只到来时在寒风中站在屋外迎接来宾，并在庆典上喝得酩酊大醉才是疾病爆发的原因。
9 Unless we ran out of food during the quarantine and all starved to death; in that case, human rhinoviruses would die with us.
9． 除非我们在隔离期间吃光了所有粮食并被饿死。在这种情况下，人类鼻病毒也会消亡。