Revision UNIT2:

- present perfect: 

* Write affirmative, negative and interrogative sentences

* just, already, yet

- present perfect or past simple:

 * exercise 1 

- past simple or past perfect:

                                                                            * exercise 2 

 - vocabulary exercises related to crime , crime 2

Review present perfect / past simple

- Present perfect
http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises
http://www.ego4u.com/en/cram-up/tests/present-perfect-simple-1
- Present perfect or past simple
http://www.ego4u.com/en/cram-up/grammar/simpas-preper/tests?test1
- just / yet / already / ever / never
http://www.grammarbank.com/ever-never-just-already-yet.html