软件的可维护性
参考答案：
软件能够被理解、校正、适应及增强功能的容易程度。
Mr. White _____ a lot of places of interest in China.[ ]
A. have gone to
B. has gone to
C. have been to
D. has been to
锁闭的进路应能随列车车列的正常运行而（）。
A.自动取消
B.自动出清
C.自动解锁
D.自动关闭
