1) beautiful-ugly 2) dark-light 3) human - можно написать not a human но я не уверена 4)happy-unhappy 5)cold-hot 6) difficult-easy 7)important -unimportant,inconsiderable 8)warm-cool , chill 9) regular-irregular , casual10)good - bad 11)far - near 12)unhealthy- healthy 13)unfriendly-friendly 14)safe- insecure, unsafe 15)heavy- light , slight