题目

（2010·浙江杭州高级中学高三第二次月考）    17. At the class meeting, some top students introduced several _____ to the study of English.    A. approaches        B. means             C. methods          D. ways 答案：A下列式子中正确的是(   ) A.3a+2b=5ab  B.   C.    D.5xy-5yx=0