B1. use the Definite Article 'the':
a. only one: the world, the earth, the sun, the sky, the sea, the ground, the country, the end of this month, but space (e.g. the Earth rotates, it also moves, or revolves, around the Sun.)
b. only one in that place or in those surroundings. (e.g. We live in a small village next to the church (= the church in our village))
c. We have already mentioned it. (e.g. When we were on holidays, we stayed at a hotel. Sometimes we ate at the hotel and sometimes we went to a restaurant.)
d. to say something about all the things referred to by a noun (e.g. The wolf is not really a dangerous animal (= Wolves are not really dangerous animals.))
e. with adjective (without noun, always plural in meaning): the blind, the dead, the deaf, the disable, the elderly, the homeless, the injured, the old, the poor, the rich, the sick, the unemployed to talk about groups of people, the young, etc. (e.g. She works for a group to help the disabled.)
f. with a superlative adjective (e.g. It is the oldest building in the town.)
g. use 'the' before same (the same) (e.g. Your pullover is the same colour as mine.)
Idiom 365
field day : an enjoyable day or circumstance
Example: The boss was gone and we had a field day today.