add and changed的用法和样例：
- Describes how to add and change code groups using Mscorcfg. Msc.
- Wiki sites track changes as people add and change content.
- The tire was whipped off and changed in jig time.
- We must also be able to add and change its identity at will, even after the record has been stored away.
- He dropped off at the square and changed to a suburban bus.