virus

流感病毒在拥挤的地方传播得很快。

A flu ___virus can spread quickly in crowded places.

医生说是病毒引起了这种疾病。

The doctor said it was a ___virus that caused the illness.

我的电脑行为异常，我怀疑是病毒。

My computer has been acting strangely, and I suspect it's a ___virus.