构造速度是指车辆在设计时,允许车辆运行的最大速度。。
参考答案:对
为避免损伤牙龈组织,上颌前牙区舌侧基托边缘应远离龈缘()
A.1~2mm
B.2~3mm
C.3~4mm
D.4~6mm
E.6~8mm
There isn't _____ in this lesson. [ ]
A. something difficult
B. difficult something
C. anything difficult
D. difficult anything