单项选择题
A. substance : air B. water : density C. level: ramification D. numbers : matrix E.agents : reaction
A.comprehension : pedagogy B.interpretation: language C. orthography : philately D. badminton : athletics E. oration : elocution
A. embellish : austere B.depurate : rare C. vary : conspicuous D. compress : volatile E. instruct: awkward