Dear Disney, Last weekend, the four members of my family spent an enjoyable holiday at the Magic Kingdom—Disneyland. And one event made our visit seem truly magical. We got to the front of the lin
下列反应过程中，同时有离子键、极性键和非极性键的断裂和形成的是A．NH4ClNH4↑+HCl↑ B．NH3+CO2+H2O====NH4HCO3C．2NaOH+Cl2==== NaCl+NaClO+H2O D
如图所示，在倾角θ=30°、足够长的斜面上分别固定着两个物体A．B，相距L=0.2m，它们的质量mA=mB=1kg，与斜面间的动摩擦因数分别为和．在t=0时刻同时撤
—When will the 2010 World Expo(世博会) come to a close? —It’ll close at the end of ________. A．September B．October C．November D．December
－Hi, Betty. Your skirt looks beautiful.－_________. A. Really? B. Oh, no. C. Thanks a lot.
如图是某些同学根据实验数据画出的图像,下列说法中正确的是( ) A.形成图甲的原因是平衡摩擦力时长木板倾角过大 B.形成图乙的原因是平衡摩擦力时
Soccer is not a violent game. But players can hit the ball with their head to purposely change the direction of the ball. In the sport this move is known as a header. Unfortunately, they may sometim
下列药品中，不需要密闭保存的是 A．浓盐酸 B．浓硫酸 C．碳酸钠 D．烧碱
