He forgot to turn off the light.

　　他忘记关灯了。（未关）

　　Remember to go to the postoffice afterschool.

　　记得放学后去邮局。（未去）

　　He forgot turning off the light.

　　他忘记关了灯。（已关）

　　Don’t you remember seeing the man before？

　　难道你不记得之前见过这个人吗？（见过）

　　17.到达…...

　　reach+地点

　　getto+地点

　　arrive+in+大地点

　　arrive+at+小地点

　　He reached London yesterday.=He got to London yesterday.=He arrived in London yesterday.

　　他昨天到的伦敦。