At, In and On
People! How have you been through the day? was it good? I hope so... I've always wanted to ask an important question regarding to an integral part of the English language: How can we know which preposition (at, on, in) we need to use in certain sentences. For instance: we need to say:
On 14th of december I'll celebrate my birthday party and not
In 14th of... Thank you in advance!