28,54,106,210,( )
A.316
B.420
C.418
D.450
参考答案:C
They just walk around the town center, many of their friends. [ ]
A. see
B. seeing
C. seen
下列不属于软件工程3个要素的是( )。
A.工具
B.过程
C.方法
D.环境