A:Fifth; five
B:Five; fifth
C:Fifth; fifth
D:Five; five
A woman____ ____ by a self-driving car as she walked her bicycle across a street.
如果点C、D在线段AB上,|AC|=|BD|,那么下列结论中正确的是( )
该小组发现 f(t) 随时间 t (分钟)的变化规律( f(t) 越大,表明学生的注意力越集中)如下: f(t)={100at10−60(0≤t≤10)340(10<t≤20)−15t+640(20<t≤40) ( a>0 且 a≠1 ).
若上课后第 5 分钟时的注意力指标为 140 ,回答下列问题: