exclamatory rule / !

[onedayatatime73]

Can someone (mrsz?) please help as I am trying to help 7yr dd with her homework and i am confused with the new rule.

So the first bit I think I get which is that an exclamatory SENTENCE has to start with what or how, and contain a verb.

But then I am confused - does a command have a an ! Eg is it
Sit down and shut up!
Or
Sit down and shut up.
But it is called a command and not an exclamatory sentence because it doesn't have a how/what. Is that right?

And can you still use an ! After a single word eg
Stop!
And again that is a command?

Then she has to identify what sort of sentence lots of examples are
Are they
Statements
Questions
Commands
Or
Exclamatory sentences.

On of the examples is
"Oh no"
Am I right in presuming this is a statement as it's not a command, and can't be an exclamatory sentence as doesn't have what/ how?

Sorry. Finding this so confusing.

. Why isn't the second one a sentence? If I changed the first to "What difficult homework to do!" would that be ok?

deciding not to mention my degree in English

This is from Mary Bousteds speech
"Do you know, as an experiment two weeks ago, I took questions from the key stage 2 spelling, punctuation and grammar (SPAG) tests to a university seminar, attended by MA and PhD graduates . I gave them the test questions and allowed them to confer – they could answer about half of them correctly. And just to reassure you, they were highly able writers. Let us remind ourselves, the SPAG tests are to be taken by 11 year olds."