forget to do ：忘记要去做某事；而forget doing：忘记已经做了某事.
forget：及物动词 vt.
1.忘记[+to-v][+v-ing][+(that)][+wh-]I forgot posting the letter. 我忘了信已寄出.Don't forget to post the letter. 别忘了去寄信.Sorry, I've forgotten your name. 对不起,我忘了你的名字.
2.忘记带(或买等)I forgot my keys. 我忘了带钥匙了.
3.不再把...放在心上Let's forget our disagreements. 我们不要再提我们之间的争吵了.
4.忽略;忽视;怠慢Don't forget the waiter. 不要忘了给侍者小费.
5.不再考虑;放弃If we can't get any financial backing, we might as well forget the whole thing. 如果得不到经济上的支持,我们还是放弃整个计划好.