Exercise on Present Perfect Simple, positive, negative, interrogative sentences. Positive with "never"

http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises?04

http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises?05


http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises?06

http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises?07