若函数()的部分图象如图所示，则有 A． B． C． D．
如图12-3-4所示，一个饮料瓶装有多半瓶水，用刻度尺标出水的深度为h1然后将该瓶倒置，水面到瓶底的高度为h2,若再用三角板和刻度尺配合，测量瓶底的
Where __________ she ___________ from? A. does, come B. is , come C. does, comes
No matter how frequently _______, the works of Beethoven still attract people all over the world. A. performed B. performing c. to be performed D. being performed
如图6所示，真空中O点有一点电荷，在它产生的电场中有a、b两点，a点的场强大小为Ea，方向与ab连线成60°角，b点的场强大小为Eb，方向与ab连线成30°角
下列各微粒属于等电子体的是A. N2O4和 NO2 B. CH4和NH4+ C. CO2 和NO2 D. C2H6 和N2H6
In some parts of the world, tea ________ with milk and sugar.A. serves B. serving C. is served D. served
如图所示，一质量为M的小车停放在光滑水平面上，车上放着一个质量为m的物块，物块与车面的动摩擦因数为μ，现给m一水平向右、大小为的瞬时冲量，
D．
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