A: 大小有关
B: 方向有关
C: 作用点有关
D: 大小、方向和作用点都有关
读一读,连线。
①How is the weather? ____ A. Yes, we can.
②How many birds are there?____ B. No, I don't.
③Can we ride bikes there?____ C. It's cloudy.
④Is it windy today? ____ D. There are four birds.
⑤Do you like the rain?____ E. No, it isn't.
禹死后,启继承父位成为夏朝第二代国王,“公天下”变成了“家天下”,这标志着下列哪一制度的出现( )