1. it was considerate of you to visit my mother every day and (to) bring me your notes to help me with the studies.

(1)it 做形式主语，后面的两个并列的不定式做真正的主语。

(2)bring sth. to sb. = bring sb. sth.

(3) to help me with studies 不定式短语，在此做目的状语

(4) and 后面的不定式 to 可以省略，为了避免并列句重复

2. it's a pity that few students nowsdays are keen on reading classics.

it做先行主语，后跟主语从句。