My time in the middle school was one of ________ periods of my life.
Which city is , Beijing or Shanghai?
秦岭—淮河一线是我国一条重要的地理分界线,下列叙述正确的是 ( )
长时间行走使脚掌磨出了水泡,几天后水泡消失.此时水泡中的液体主要渗入( )
我国人口分布的基本特点是( )