The thing about grammar in our native language is that we are so accustomed to using sentence structures automatically it can be difficult to change poor habits. However, there are generally lots of English as a foreign/additional language (EFL/EAL) teaching sites that tackle the technical elements.
1 – BBC Learning English – an outstanding free online course from beginner right up to complex language, which uses BBC footage and additional materials. This is the ‘towards advanced’ course link: https://www.bbc.co.uk/learningenglish/english/course/towards-advanced
This is the course overview for that level:
https://www.bbc.co.uk/learningenglish/english/hygiene/towardsadvanced-syllabus
Apostrophes (see below) recur at different levels, here in the ‘upper intermediate’ course:
https://www.bbc.co.uk/learningenglish/english/course/upper-intermediate/unit-1/session-4
2 – mmmEnglish – an Australian EFL teacher called Emma who smiles her way through all sorts of linguistic points including the passive voice, as referred to above:
[MEDIA=youtube]nkAyggAM1q4[/MEDIA]
3 – English with Lucy – a London-based EFL teacher who specialises in idioms and all things British. Here she is on ‘apostrophes’ (skip the first 2mins 30)
[MEDIA=youtube]YDB2Maro5H8[/MEDIA]
Now for that niggling grammatical concern, the RANDOM APOSTROPHE!
It may help to indulge in a little grammatical anthropomorphism.
THE BELONGING (OR POSSESSIVE) APOSTROPHE
Meet Bertha (or Bruce/Beatrice/etc) the Belonging Apostrophe. Bertha’s only job in life is to tell you that there is possession involved. If you find it easier, consider this possession in the spiritual sense, but it is just about something belonging to someone/something.
The cup belongs to Simon. It is Simon’s cup.
The cup belongs to Maria. It is the cup of Maria. It is Maria’s cup.
The cup belongs to James. It is the cup of James. It is James’s cup. (It can also be James’ cup. This is also fine but choose one and stick with it.)
The (sports) cup belongs to the class. It is the cup of the class. It is the class’s cup.
The (drinking) cups belong to the class. They are the cups of the class. They are the class’s cups.
Things can get a bit more complicated when there is already a double 's', but if you look for Bertha, she is right there.
The cup belongs to the boss. It is the boss’s cup.
The cups belong to the bosses. They are the bosses’ cups.
Bertha realises that "the bosses's cups" would be overkill. That's not her style.
The (drinking) cups belong to the classes. [There are 500 drinking cups that belong to many different classes.] They are the classes' cups.
BUT....
If the item (cup, etc) belongs not to him or her but to 'it', THERE IS NO APOSTROPHE! You will see this mistake A LOT.
The door of the car was scratched. Its door was scratched.
The leg of the table is broken. Its leg is broken.
THE CONTRACTION APOSTROPHE
CONTRAST THIS with Connie/Connor/etc the CONTRACTION apostrophe. Connie’s role is to save space – to replace missing letters. She’s busy when you “won’t or don’t or can’t”. She works when “it isn’t (sunny/rainy/possible/etc)”.
She also works, and this is the key one, when it ‘IS’.
It is sunny. It’s sunny.
Also, ‘HAS’.
It has been sunny all week. It’s been sunny all week.
Also:
Who is at the door? Who’s at the door?
Who would have thought it? Who'd've thought it? [This is more complex!]
BUT
Whose cups are these? (It makes no sense to use an apostrophe because there is no belonging and no contraction.)
HOWEVER
The “ ’s ” is NOT used for plurals. There is nothing missing so no need for Connie. There is no possession/belonging involved, so no Bertha. There is no need for a random apostrophe. It’s just wrong. See photo below taken this morning at Westminster tube station.
The rare exception to this is for abbreviations. One way to remember this is that there are some letters missing so Connie (who deals with contractions/missing letters) steps in to help:
He received four A’s and two B’s.
We hired three M.D.’s and two F.O.’s.
Be sure to cross your t’s and dot your i’s.
Our M.P.’s are being wrongly instructed in grammar on the daily commute. See photo below...
Happy scribbling!