若一个多边形的每一个外角都等于45°，则这个多边形共有（ ）条对角线。
20
A．( Because they may not judge speeds very well
B．( Because they may step into the road for convenience
C．( Because they cannot run very fast
D．( Because they may become nervous easily
第五套人民币1999年版的钞票纸张中有两种有色纤维，这些纤维是（）。
A.红色和蓝色
B.红色和绿色
C.绿色和红色
