用3厘米、3厘米、7厘米的三根小棒，首尾相接可以围成一个等腰三角形．…______．
因为3+3＜7，所以本组小棒不能围成三角形；
故答案为：×．
HDLC 是一种（ ） 协议。
A．面向比特的同步链路控制
B．面向字节计数的异步链路控制
C．面向字符的同步链路控制
D．面向比特流的异步链路控制
As I grew up in a small town at the foot of a mountain, the visit to the village ____ scenes of my
childhood. [ ]
A. called up
B. called for
C. called on
D. called in
