The definite article with a modified noun

Question

I am very perplexed. I saw this in an article:

1)

• "Fairuza plays Stacia, a tough young woman who's the passenger on a bus that breaks down on the way to Spokane."

I thought saing this means she is the only passenger, but it it obviously not the case.

• Duty to the passenger on a bus, adult or child, begins when the person boards that vehicle.

Why "the" here? It is obviously not the only possible passenger on a bus.

2) Talking generally:

• "It will cause harm the passengers on a bus"

Well, passengers can be used with "the" because we do have specific passengers in mind - those on a general bus, BUT - does it specify the quantity of passengers I talk about? Can it mean that I talk about some of them?

• "It will cause harm the passenger on a bus"

As we are talking about any passenger that is specific because he is a passenger of a bus, can we use "the passenger" talking generally? And does it say anything whether it is the only passenger who is traveling on a bus? Can it mean one of them?

Please, help.

Answer 1

Minus the opening clause in the first sentence ('Fairuza plays') it would make more sense to have 'a passenger' in the sentence you've quoted as presumably there would be more than one passenger on the bus in question and all would be affected by the breakdown. The context set by the opening clause is important though - Stacia is a member of a defined list of characters that appear in either a play, movie or television production. The relative clause that follows functions to identify which of the characters she is - the information given is specific enough for a definite identification (there is only one character of which the description is true), so the use of the definite article is appropriate given this context.

Responding to your second section, both constructions you cite are general cases as 'a bus' sets an indefinite (general) context. The first formulation would normally* imply all the passengers will be harmed - if you wish to leave open the possibility of a subset being affected, then either change 'will' to 'can' or include 'some of' as per:

• It can cause harm to the passengers on a bus
• It will cause harm to some of the passengers on a bus

While it would normally be preferable to use 'a passenger' to consider a general case focusing on an individual but representative passenger, 'the passenger' can be idiomatic - especially when employed to emphasize it as the current element of a general case under consideration (in distinction from other elements previously discussed eg. 'the driver', 'the company' etc.).

_{*There is a slight ambiguity here, as 'the passengers' can either be construed as a plurality of passengers (the normal case - in which case, what I said stands) or as a singular group of passengers (in the latter case, we could say the group will be harmed without necessarily all members of the group experiencing harm)}