2017-2018 28 1 2 A h d n di n p n B q b y n tu n C l p s ng ch ng D b l u ch ng w i 2 2 A B C D 3 3 A B C D 4 ( ) 3 A B C D 5 3 A B C D 6 3 A B C D 7 3 A B 20 C D 8 6 A A B A B A A B C B C 3 A B C 3 9 (4 ) (1) ( 2 ) (2 ) (2) (2 ) 10 (4 ) 21 11 3 1 2 3 12 4 1 2 13 4 ! 14 2 A B C D 15 2 A B C D 16 2 A B C D 17 4 1 2 (16 ) X 17 30 , 200 20 30 18. (4 ) 19. (4 ) 20. (4 ) 21. (4 ) (50 ) 500 100 200 300 400 500 600