现在完成时：
have/has + 动词过去分词
She has already aired the room.
She has not aired the room.
Has she already aired the room?
Yes,she has. No,she hasn’t.
What has she done?
do/does/doing/did/done
go/goes/going/went/gone
动词原形变过去分词规则：
1. +ed
2. 以不发音的e结尾，+d
3. 辅音+y结尾，变y为i，+ed
4. 重读闭音节（辅元辅），双写最后一个字母，+ed
5. 特殊情况
