You're supposed ______ your room up before you go out.
A:to clean
B:clean
C:cleaning
支撑物高度h(cm)
10
20
30
40
50
60
70
80
小车下滑时间t(s)
4.23
3.00
2.45
2.13
1.89
1.71
1.59
1.50
下列说法错误的是( )
“自古英雄多磨难,从来纨绔少伟男”,告诉我们逆境有利于成才;“一朝被蛇咬,十年怕井绳”,又说明挫折对人成长的负面效应。某班学生就“挫折与成才的关系”举行辩论会,请你参与。
①∠BAD=∠ACD;②∠BAD=∠CAD.