Grammar structures

I need help in identifying the grammatical structures in the following sentences and i need it very quickly. Help!!!
I needn,t have bought that milk.
He played truant.
I recommend staying at the Hilton.
I remembered to post the letter. vs I remembered posting the letter.
She,s been to Canada.
Example:
He was watching TV when his girlfriend phoned.
form:
s+was/were+verb+ing(when+past simple)
(past continous)
thanks