UNIT 2
Grammar practise
MODALS OF OBLIGATION
https://learnenglish.britishcouncil.org/en/grammar-reference/modals-1
http://www.learnenglish-online.com/grammar/modals/tests/modalobligation
lhttp://www.perfect-english-grammar.com/modal-verbs-of-obligation-exercise-1.html

PRESENT PERFECT SIMPLE AND PROGRESSIVE
https://www.ego4u.com/en/cram-up/grammar/prepersim-preperpro
http://www.english-grammar.at/online_exercises/tenses/present-perfect1.htm

h