"我忘了他的生日！"

Translation: I forgot his birthday!

[ymaarrawi]

What's the difference between 忘记 & 忘？

[Pcookie334]

忘记 is used very little. 忘了 is a more colloquial way of saying forgot

[FuCnSW]

Same. But be careful the oral speaking habit.

[Terence364703]

I feel bad now. :(

[o-chefe]

F