【单选题】如图所示, A 、 B 两车相距 S 0 =25m , A 以 v= 4m /s 速度匀速行驶, B 以 v 0 =10m/s 初速度和 a =2m/s 2 加速度同方向减速行驶。下列说法正确的是( )
【单选题】拉深常见的质量缺陷有起皱和拉裂。关于起皱,说法错误的是
【多选题】在某一高度以 v 0 = 20 m/s 的初速度竖直上抛一个小球 ( 不计空气阻力 ) ,当小球速度大小为 10 m/s 时,以下判断正确的是 ( g 取 10 m/s 2 )
A.
小球在这段时间内的平均速度大小可能为 15 m/s ,方向向上
B.
小球在这段时间内的平均速度大小可能为 5 m/s ,方向向下
C.
小球在这段时间内的平均速度大小可能为 5 m/s ,方向向上
【单选题】They are trying to make sure that 5G terminals_________ by 20 22 for the Beijing Winter Olympics.
B.
will have been installed
【单选题】They are trying to make sure that 5G terminals_________ by 2022 for the Beijing Winer Olympics.
B.
will have been installed
【判断题】Miss Smith calls Mr. Black to cancel the meeting tomorrow.
【简答题】They are trying to make sure that 5G terminals ____(install) by 2022 for the Beijing Winter Olympics.