Can anyone help?

I need to analyse the following sentences in terms of identifying
a)the form
b)the function/meaning
c) possible student difficulties (form, function and phonology)
d)possible context through which i could teach the language

Sentences are:
1. 'I wish i'd known'

2.a. 'I'll visit my grandmother tomorrow.'
2.b. 'I'm going to visit my grandmother tomorrow.'

3.a. 'The students had left when the bell rang.'
3.b. 'The students left when the bell rang.'
3.c. 'The students were leaving when the bell rang.'

The task for number 2 and 3 is to deal with the differences between the sentences and not to examine them indivisually.

Can anyone help me???

(email - [email protected])

Thanking you muchly!!!