forget to do sth. 意為“忘記做某事（動作還沒有發(fā)生）”
forget doing sth. 意為“忘記做過某事（動作已發(fā)生）”
例句：Don't forget to bring your photo here. 別忘了把你的相片帶來。I have forgotten giving the book to him. 我忘記我已把書給了他。
go on to do sth. 意為“做完一件事，接著做另外一件事（兩件事之間可能有某種聯(lián)系）”
go on doing sth. 意為“繼續(xù)做下去”。
例句：After reading the text, the students went on to do the exercises. 學生們讀完課文后，接著做練習。
It's raining hard, but the farmers go on working on the farm. 雖然天正下著大雨，但農(nóng)民們繼續(xù)在農(nóng)場干活。