English Students Level 3.

Negative and Interrogative sentences of past simple tense.

Exercises:

http://web2.uvcs.uvic.ca/elc/studyzone/330/grammar/pastnq1.htm
http://esl.fis.edu/grammar/single/pastsimp2.htm
http://www.english-room.com/negative_6.htm

Past simple "Had" and "Could"

Explanation - use of "HAD":

https://www.youtube.com/watch?v=n5hLgIY_tzo

Exercises:

http://www.englisch-hilfen.de/en/exercises/tenses/have.htm
http://www.englishexercises.org/makeagame/viewgame.asp?id=638

COULD

Explanation: 

Exercises:

http://www.englishexercises.org/makeagame/viewgame.asp?id=7710

http://www.englishgrammarsecrets.com/could/exercise2.swf