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b. is c. costs is ______ than Sam. a. yong b. younger c. youngest 16. Tommy is _____ in our school. a. tall b. taller c. the tallest 17. I think science is the _____ subject. a. interesting b. more interesting c. most interesting 18. This is ____ elephant. a. a b. and c. an is ______ bag. a. hers b. she c. her 20. Give_____ the book, please. a. my b. I c. me