有18个小朋友排成一路纵队,每两个小朋友之间相距1米,这路纵队全长大约______米.
(18-1)×1,
=17×1,
=17(米).
答:这路纵队全长大约17米.
故答案为:17.
His sister left home in 1998, and__________ since.
A.had not been heard of
B.has not been heard of
C.had not heard of
D.has not heard of
辨疼痛时,朝轻暮重,属()之证;朝重暮轻,属()之证。