E.S.O.: Passive voice, present & past

Log onto the following web sites and do the exercises on the passive voice, present and past:

http://www.ego4u.com/en/cram-up/grammar/passive/exercises

http://www.ego4u.com/en/cram-up/grammar/passive/exercises?simple-past

http://www.ego4u.com/en/cram-up/grammar/passive/exercises?simple-present

http://www.ego4u.com/en/cram-up/grammar/passive/exercises?simple-past

http://www.isabelperez.com/hotpot/dogphone.htm

http://www.isabelperez.com/hotpot/passivemobiles.htm

Write any doubts or comments in 'comentarios'.