Can anyone explain the ambiguity in these sentences in DS's grammar homework?

[cornflakegirl]

DS (Y5) has brought home a grammar workbook that includes a section on compound sentences. It says:

"You can use a comma with a conjunction to join two sentences together. When you join two main clauses like this, you make a compound sentence. The comma helps to avoid ambiguity."

The exercises are then to join the following sentences with a comma and a conjunction:

1. We played rounders. The other team won.
2. I like sausages and ice cream. I do not like them on the same plate.
3. I had a big breakfast. I'm not really hungry now.

I can't seen how any of those compound sentences would be ambiguous without a comma. Can anyone enlighten me?

I can't see that any of them need both a comma and a conjunction. The second one could if the conjunction needed was 'and' but it's not, it's 'but'

They need a semi colon rather than a comma, surely?

We played rounders, and the other team won.

I like sausages and ice cream, but I do not like them on the same plate.

I had a big breakfast, and I'm not really hungry now.

(I think) looking at:
www.grammar-monster.com/lessons/conjunctions_and_commas.htm

Usually in compound sentences I would use a conjunction and no comma. I'd use a comma in a complex sentence but only where the sub clause comes first or where the sub clause is in the middle of the main clause. So:

We played rounders and the other team won.

Shouting loudly, Emma hit the ball.

Emma, shouting loudly, hit the ball.

Bigger - yeah that's what I think.
mrsminiver - a semi colon would work instead of a conjunction, but both would be weird!
Gemma - yeah, I get that's what the book is saying you need to do, just no idea why they think the comma is necessary. I actually think those sentences look clunky with a comma. It interrupts the flow.

Was going to say the same as Gemma except I think the third one should be

I had a big breakfast, so I'm not really hungry now.

Antoinette - completely agree that if you have a subordinate clause you need commas (or as I learnt it at school, if there's a bit that you can take out and the sentence still makes sense, put commas round it). But the book is talking about joining main clauses that can be sentences by themselves.

I realise it's not just the book advocating it - have found other sites similar to the one Gemma linked. But I think that comma usage has changed over time and that stylistically most people would prefer the sentences without commas. (Unless they really are ambiguous.)

owl.english.purdue.edu/owl/resource/598/01/

There are a number of conjunctions that could work in each of the sentences, depending on context. Eg "We played rounders, so the other team won" if the team was expecting to play football ;) And I think that one would need a comma, to distinguish between so = consequently and so = in order that.

cornflake I agree-I think the book is wrong. I wouldn't use commas in any of the sentences in your OP.

Drowned - that site still just states the rule. I disagree that that is how English is generally written.

It's like the Oxford comma - sometimes you need it to avoid ambiguity, but I think a lot of style guides recommend avoiding it. Of course, it's a matter of personal choice. But I wouldn't teach children that they must use it.

Comma splicing

cece - sorry, didn't see your response. The book isn't trying to comma splice, as it's using a conjunction as well as a comma.

The last example on the page you linked is:
'Jim usually gets on with everybody, as he is an understanding person.'

Which I think is what the book is recommending, but I don't see what the comma adds. I don't think that the sentence is at all ambiguous without the comma.

It strikes me that ambiguity is not the issue - most of the examples above clearly have one meaning with or without the comma. However, the use of the comma might aid readability.
For example, take the sentences:

1. Jim gets on with everything as quickly as possible.
2. Jim gets on with everything as he is a very efficient person.

If I am reading 2 for the first time, then when I hit "as" there is a tension (sub-consciously) over whether the "as" is introducing an adverbial type phrase (as it does in 1) or a clause (as it does in 2). Obviously, that tension is resolved once I get to the end of the sentence. By putting a comma in front of "as" in 2, I give the reader a little advanced clue that it is a clause - I can imagine taking a quick breath before "as" in 2, but not so much in 1.

It's not a hard and fast rule it just seems that a comma used sensibly can give the reader some clues as to the structure of the sentence.

Actually, looking back to the first example: I'm reading "We played rounders and-" for the first time and there is now a tension in my mind - is the structure going to be "rounders and football" or "rounders and [whole new clause]". A comma before the "and" makes the "and football" option less likely and so I am not tripped up reading the rest of the sentence.

Slightly off topic - my example of where a comma before the "and" might remove ambiguity:

For the inspiration to learn the cello, I would pay tribute to my parents, Jacqueline du Pre and J S Bach.

DadDadDad - thanks, I think you've nailed it! I still don't think I would use a comma in those sentences, but at least now I can explain to DS why some people might. Ta very much!

The team played rounders and football was not on the agenda.

Now admit it - when you read that you had to backtrack for a fraction of second, because your brain was thinking and were being paired, when actually "and" was introducing a whole new clause. A comma would have helped. (I believe these are called garden path structures). So, I'm saying consider it for your reader's sake!

But, anyway, thanks for commenting on my response. . I'm sometimes left wondering if any cares / likes / even reads my comments on Pedants Corner, where traffic can be slow.