回归测试是哪一类维护中最常用的方法 ( )
A.校正性维护
B.预防性维护
C.适应性维护
D.完善性维护
参考答案:A
解析: 回归测试是校正性维护中最常用的方法。
Have you ever dreamed _______ in front of thousands of people at a concert, with everyone ________ your singing.
A.of…clapping and joining
B.of being…clapping and joined
C.of being…clapping and joining
D.of being…clapped and joined
试述紫外线的特点