下列()不属于系统转换的方式。
A. 直接转换
B. 并行转换
C. 分段转换
D. 渐进转换
()维护是花费成本最高的
A. 适应性维护
B. 完善性维护
C. 正确性维护
D. 预防性维护
软件系统投入使用后,总投资额度为10万元,经过2年后开始产生效益,2年后每年的效益为5万元,每年的运行成本为2万元,求投资回收期为()年。
l in the blanks with the words in the box. Change the form where necessary.evilcrueltwiststing1.How can you be so ______ to someone who never did you any harm?2.The struggle between good and _______ will never stop.3.Her words _______ his pride and his heart sank all of a sudden.4.He’s always trying to _______ my words and make me look bad.