this bacteria is virulent strain
Virulent means actively poisonous. You could use it in a sentence as, "the man had a virulent snake bite."
he came down with a virulent type of disease
The virulent strain of the virus spread rapidly through the community, causing severe illness and a high mortality rate.
This justifies the use of this word, in a sentence.
It would be used in a sentence such as: "He didn't start school that semester as he would have had to register by a certain date."
I would be more apt to use it if I understood how it is used.
The dog used to live there but its master abandoned it.
It is not that hard to use guerrillas in a sentence. See, I just used guerrillas in a sentence. The guerrillas are attacking!
Usually at the beginning, for example: Contrary to popular belief, the word contrary is used at the beginning of the sentence in which it is used.
gravity would be used in a sentence like this: The gravity of the Earth is a very important part of life.
I believe you are trying to use the word lass to refer to a girl. So in this case lass would be used as the noun of the sentence just like you would use the world girl.
Refer to your question. A question is a sentence and your sentence used the word "assault" in it. Therefore, you answered your own question.