class 5: can and can't

An easy exercise to begin with
 http://first-english.org/english_learning/english_beginners/can_can_t_exercises/03_can_english_grammar_exercises.htm

Find the correct questions
http://www.englisch-hilfen.de/en/exercises/questions/can2.htm
http://first-english.org/english_learning/english_beginners/can_can_t_exercises/04_can_can_t_negative_exercise.htm
http://first-english.org/english_learning/english_beginners/can_can_t_exercises/07_can_questions_exercises.htm

mixed exercises
http://first-english.org/english_learning/english_beginners/can_can_t_exercises/09_can_mixed_exercises_learning.htm
http://first-english.org/english_learning/english_beginners/can_can_t_exercises/10_can_can_t_mixed_exercises.htm