Practicing Success
Select the combination of letters that when sequentially placed in the blanks of the given letter series will complete the series. ab _ _ bb _ _ aa _ b a _ _ ab _ |
ababbaab aaabbbab babaabaa bbaabbaa |
aaabbbab |
a b a a b b / a b a a b b / a b a a b b a a a b b b a b |