牵牛子的性状特征有
A.形似橘瓣
B.表面黑灰色或浅黄白色
C.腹面呈棱线状
D.水浸后种皮呈龟裂状,有明显黏液
E.质坚韧
参考答案:A,B,C,D,E
We _____ spend too much time in watching TV. [ ]
A. told don't
B. told not to
C. were told not to
D. were told to not
有两颗行星A、B,在两个行星表面附近各有一颗卫星,如果这两颗卫星运动的周期相等,下列说法正确的是( )
A.行星A、B表面重力加速度之比等于它们的半径之比
B.两卫星的线速度一定相等
C.行星A、B的质量和半径一定相等
D.行星A、B的密度一定相等