1. The virulent strains had a polysaccharide capsule and formed smooth colonies on agar medium. 有毒菌株具有多糖荚膜它在琼脂培养基上形成光滑的菌落。
2. During this time they are not virulent. The viral genome may later become active, initiating production of viral particles and destruction of the host cell. 在此期间，噬菌体是无毒性的。这种滤过性染色体组以后会变得活跃，开始产生滤过性病毒粒子，破坏宿主细胞。
3. Computer viruses act like biologics in the way they can be set off: they can be virulent from the outset of the infection or they can be activated by a specific event (logic bomb). 计算机病毒的传播行为与生物病毒极其相似：它们可能从开始感染时就是致命的，可以被某些特定的事件所引发（逻辑炸弹）。
英英解释
adj.
1. extremely poisonous or injurious; producing venom
2. infectious; having the ability to cause disease
3. harsh or corrosive in tone
