A:2
B:−2
C:12
D:−12
将未装满水且密闭的矿泉水瓶,先正立放置在水平桌面上,再倒立放置,如图所示,两次放置时,水对瓶底和瓶盖的压强分别是pA和pB水对瓶底和瓶盖的压力分别为FA和FB,则( )
Shanghai ____ (be)a small town hun dreds of years ago. Now it ____ (become) a large city.
栽种于我市姜堤乐园的樱花一般在四月中旬盛开,而位于长江中游武汉的东湖樱花早在三月下旬便进入盛开期,造成这种差异的非生物因素是( )