'A or B' : plural? singular?

If B is a singular noun, as grammar books suggest, we should use singular verb form. But:

[i]Children always appreciate small gifts of money. [color=red]Mom or dad, of course, [color=red]provide a regular supply of pocket money, but uncles and aunts are always a source of extra income.

There are rare instances when justice almost ceases to be an abstract concept. [color=red]Reward or punishment are meted out quite independent of human interference.[/i]

Both sentences are excerpted from a well-known ESL textbook. Is that a right way?

Thanks

Oh wow, this is such a confusing case for me. I have learned this at school but then I forgot and never paid attention to such cases as this to see which is correct and which is incorrect.

Then, let’s see

First, about your singular/plural question

–> Mom or dad, of course, PROVIDES a regular supply of pocket money, but …
(mom or dad = either this person or the other person --> singular --> 3rd verb form)

–> … but uncles AND/OR aunts are always SOURCES of extra income
(uncles, aunts = plural --> even if you use “and” or “or” here, in total, they are still plural --> the “source” should be plural as well)

(actually I am not quite sure about this)

–> Reward or punishment IS meted out quite independent of human interference.

Reward is Count Noun and in this sentence it is singular
Punishment is Uncount Noun and so it is treated as a singular

In this sentence, you use OR, which mean one of those 2 but not both of them --> the subject is singular --> 3rd verb form

Second, about your sentences themselves

You said that those sentences are from a well known ESL textbook. If they have not been modified or cut off from a different paragraph/context, then I DON’T UNDERSTAND the way they form the first paragraph

In my opinion, it should be

“Children always appreciate small gifts of money. ALTHOUGH mom or dad, of course, provides THEM a regular supply of pocket money, uncles and aunts are always sources of extra income”

I believe there should be some other better ways to form these sentences other than the above.

The problem I found here is that there is no connection between those 2 sentences, and there is no object after the verb PROVIDE

For the second paragraph, I have not yet got a comment.

PLEASE COMMENT

Thank you, Emily

Though I am not sure, what we are talking about here are classes – mom or dad, reward or punishment and hence the plural verb forms.

“uncles and aunts are always sources of extra income”

Remove the always, and the sentence is OK.

Alternatively;" uncles and aunts become a source of extra income.

Here are some more examples:

Maybe you can’t remember when you were that age but children will run amuck when [color=red]mom or dad are not around.

From dedicated gamers to [color=red]Mom or Dad who [color=red]want to try out a game, trade-in some old games or check out the latest titles and consoles from …

… then a hefty fine in court in the presence of [color=red]mom or dad who[color=red]'ve had to take time off work and get up the previous night to go the the station,…