中小学生意外事故最多见的是()。
A.火灾
B.自杀
C.中毒
D.车祸
E.触电
参考答案:D
下列关于位移和路程的说法错误的是( )
A.沿直线运动的物体,位移和路程有可能相等
B.质点沿不同的路径由A到B,其路程可能不同而位移是相同的
C.质点通过一段路程,其位移可能为零
D.质点运动的位移大小可能大于路程
You think your ruler is very long,but his is _________yours.
A.twice as long as
B.three as long as
C.twice longer as
D.once as longer as