51. remember/forget to do sth 記得/忘記做某事(沒有發生)

　　Please do remember to post a letter forme.務必記得幫我寄信。

　　remember/forget doing sth 記得/忘記做過某事

　　I remember telling you the news before.我記得曾經告訴過你這個消息。

　　52. see sb do sth 看見某人做某事(結果)

　　see sb doing sth 看見某人正在做某事(正在進行中)

　　be seen to do sth 做某事被看見

　　I saw them play football last weekend.

　　I saw her cleaning the classroom.

　　I saw him get on the bus.= He was seen to get on the bus.

　　53. something to eat/drink 一些吃/喝的東西(詞不定式放在something等后修飾這些詞)

　　I need something to eat. 我要一些吃的東西。

　　54. spend some time (in)doing sth /on sth 花費時間做某事(注意動詞要用ing形式)(常考)

　　I spent 2 hours on homework.= I spent 2 hours in doing homework.

　　spend some money on sth/doing sth 買……花了多少錢

　　I ofen spend some money on the book. I ofen spend some money buying the book.

　　55. Sth is hard/difficult/easy to do . 做好某事很難/容易

　　The question is easy to answer.

　　56. stop to do sth停下來去某事(兩件事)(常考)

　　stop doing sth 停止做某事(一件事)(常考)

　　stop sb (from) doing sth 阻止某人做某事(常考)

　　The two girls stopped to talk to me when they saw me.

　　The two girls stopped talking when they saw me.

　　I tried to stop my father from smoking,but failed.

　　57. take turns to do sth 輪流做……

　　They take turns to do the cleaning.

　　58. tell sb (not)to do sth 叫某人去(不要)做某事

　　He tell me not to swim in that lake.

　　59. There is no need (for sb) to do sth 對某人來說沒必要做某事

　　There is no need for you to worry.

　　60. There is notime (for sb ) to do sth

　　have no time to do sth 沒時間做某事

　　There is no time to think .I have no time to do morning exercises.