B. dfrac {1)(2) . C. dfrac (2)(3) . D. dfrac (3)(4)

-dfrac (2)(3) C. dfrac (2)(3) D. dfrac (1)(9)

dfrac (1)(6)-|||-C. dfrac (1)(2) D. dfrac (1)(3)

dfrac (1)(6)-|||-C. dfrac (1)(2) D. dfrac (1)(3)

dfrac (1)(x) C. -dfrac (1)({x)^2} D. dfrac (2)({x)^3}

_(1)-(F)_(2)-|||-C. dfrac (2)(3)(F)_(1)+dfrac (1)(3)(F)_(2)-|||-D. dfrac (2)(3)(

((y+dfrac {1)(2))}^2=dfrac (3)(4) D. ((y-dfrac {1)(2))}^2=dfrac (3)(4)

大于等于dfrac (1)(2)B. 小于等于dfrac (1)(2)C. 小于等于dfrac (1)(2)D. 大于等于dfrac (1)(2)调整某种仪器1

dfrac {3)(10) C. dfrac (7)(10) D. dfrac (2)(5)

dfrac (3)(2) D. dfrac (1)(2)

dfrac (pi )(4) C. dfrac (pi )(2) D.π