为了测量冰块的密度,把水注满可均匀膨胀,质量和厚度忽略不计的正方体模具中,塞紧注水孔,利用天平测得水的质量.
北京市中心是天安门广场,这里交通便捷,但却看不到摩天大厦.用形成城市地域功能分区的原因分析,这主要是( )
—Where is Lucy? I can't find her now.
—She ___________ Shanghai on business. She ___________ back in three days.
已知集合A=x|x<3,B=x|log2x>0则A∩B=( )
若⊙O的半径为6cm,则⊙O中最长的弦为____ 厘米.