要画一个直径是6cm的圆，圆规两脚间的距离是______cm．
6÷2=3（厘米）
答：圆规两脚分开的距离是3厘米．
故答案为：3．
Wind _______ electricity widely in many parts of the world.
A．is used to produce
B．is used to producing
C．used to produce
D．used to producing
怎样才能将同一特效快速运用于不同的层上？
