1. Colds are infectious, and so are some eye diseases.
    感冒是传染的，有些眼病也是传染的。

2. Their enthusiasm was infectious.
    他们的热情有感染力。

1. infectious的反义词

1. 感染性的：过敏性又分为季节性(seasonal)与全年性(perennial非过敏性鼻炎分为感染性的(infectious)及非感染性的(non-allergic non-infectious). 前者最常见的就是病毒感染,也就是感冒,或是因细菌的继发性感染;

2. 传染：SEIR的四个字母分别代表易感(Susceptible)、潜伏(Exposed)、传染(Infectious)和康复(Recovered)病人. 美国和加拿大的科学小组研究了205个SARS病例;英国和中国香港的科学小组则研究了香港SARS最初10周的流行趋势. 都得出了一个相同的结论:如果不加控制,

3. 传染性的：inexhaustible 取之不尽的 | infectious 传染性的 | inferior 低人一等的

1. 传染的;传染性的
    A disease that is infectious can be caught by being near a person who has it.

    e.g. ...infectious diseases such as measles...
           类似麻疹这样的传染病
    e.g. These viruses affect children and are highly infectious.
           这些病毒会侵袭儿童，而且具有很强的传染性。

2. 有感染力的;易传播的
    If a feeling is infectious, it spreads to other people.

    e.g. She radiates an infectious enthusiasm for everything she does...
           她做任何事情都充满一种极富感染力的热情。
    e.g. There was a peal of laughter down the phone, which Harry found infectious.
           电话里传来一阵响亮的笑声,哈里也不禁受其感染。